[Code of Federal Regulations]
[Title 7, Volume 11]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 7CFR1755.522]
[Page 596-657]
TITLE 7--AGRICULTURE
CHAPTER XVII--RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE
PART 1755--TELECOMMUNICATIONS STANDARDS AND SPECIFICATIONS FOR MATERIALS, EQUIPMENT AND CONSTRUCTION--Table of Contents
Sec. 1755.522 RUS general specification for digital, stored program controlled central office equipment.
(a) General. (1) This section covers general requirements for a
digital telephone central office switching system, which is fully
electronic and controlled by stored program processors. A digital
switching system transfers information which is digitally encoded from
any input port to a temporarily addressed exit port. The information may
enter
[[Page 597]]
the system in either analog or digital form and may or may not be
converted to analog at the exit port depending on the facility beyond.
The switching system shall operate properly as an integral part of the
telephone network when connected to physical and carrier derived
circuits meeting RUS specifications and other generally accepted
telecommunications practices.
(2) The output of a digital-to-digital port shall be Pulse Code
Modulation (PCM), encoded in eight-bit words using the mu-255 encoding
law and D3 encoding format, and arranged to interface with a T1 span
line.
(3) American National Standards Institute (ANSI) Standard S1.4-1983,
Specification for Sound Level Meters, is incorporated by reference by
RUS. This includes S1.4A-1985 that is also incorporated by reference.
This incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
Copies may be obtained from ANSI Inc., 11 West 42nd Street, 13th Floor,
New York, NY 10036, telephone 212-642-4900. Copies may be inspected
during normal business hours at RUS, room 2838-S, U.S. Department of
Agriculture, Washington, DC 20250 or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(4) American Society for Testing Materials (ASTM) Specification B
33-91, Standard Specification for Tinned Soft or Annealed Copper Wire
for Electrical Purposes, is incorporated by reference by RUS. This
incorporation by reference was approved by the Director of the Federal
Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies
may be obtained from ASTM, 1916 Race Street, Philadelphia, PA, telephone
215-299-5400. Copies may be inspected during normal business hours at
RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250
or at the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
(5) Bell Communications Research (Bellcore) document SR-TSV-002275,
BOC Notes on the LEC Networks--1990, March 1991, is incorporated by
reference by RUS. This incorporation by reference was approved by the
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and
1 CFR Part 51. Copies may be obtained from Bellcore Customer Service, 60
New England Avenue, Piscataway, NJ 08854, telephone 1-800-521-2673.
Copies may be inspected during normal business hours at RUS, room 2838-
S, U.S. Department of Agriculture, Washington, DC 20250 or at the Office
of the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(6) Bellcore TR-TSY-000508, Automatic Message Accounting, July 1987,
is incorporated by reference by RUS. This incorporation by reference was
approved by the Director of the Federal Register in accordance with 5
U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bellcore
Customer Service, 60 New England Avenue, Piscataway, NJ 08854, telephone
1-800-521-2673. Copies may be inspected during normal business hours at
RUS, room 2838-S, U.S. Department of Agriculture, Washington, DC 20250
or at the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
(7) Federal Standard H28, Screw-Thread Standards for Federal
Services, March 31, 1978, is incorporated by reference by RUS. This
includes: Change Notice 1, Federal Standard, Screw-Thread Standards for
Federal Services, May 28, 1986; Change Notice 2, Federal Standard,
Screw-Thread Standards for Federal Services, January 20, 1989; and
Change Notice 3, Federal Standard, Screw-Thread Standards for Federal
Services, March 12, 1990. This incorporation by reference was approved
by the Director of the Federal Register in accordance with 5 U.S.C.
552(a) and 1 CFR part 51. Copies may be obtained from the General
Services Administration, Specification Section, 490 East L'Enfant Plaza
SW, Washington, DC 20407, telephone 202-755-0325. Copies may be
inspected during normal business hours at RUS, room 2838-S, U.S.
Department of Agriculture, Washington, DC 20250 or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700, Washington,
DC.
(8) Institute of Electrical and Electronics Engineers (IEEE) Std
455-1985, IEEE Standard Test Procedure for Measuring Longitudinal
Balance of
[[Page 598]]
Telephone Equipment Operating in the Voice Band, is incorporated by
reference by RUS. This incorporation by reference was approved by the
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and
1 CFR part 51. Copies may be obtained from IEEE Service Center, 445 Hoes
Lane, P. O. Box 1331, Piscataway, NJ 08854, telephone (201) 981-0060.
Copies may be inspected during normal business hours at RUS, room 2838-
S, U.S. Department of Agriculture, Washington, DC 20250 or at the Office
of the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(9) Institute of Electrical and Electronics Engineers (IEEE) Std
730-1989, IEEE Standard for Software Quality Assurance Plans, is
incorporated by reference by RUS. This incorporation by reference was
approved by the Director of the Federal Register in accordance with 5
U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from IEEE
Service Center, 445 Hoes Lane, P. O. Box 1331, Piscataway, NJ 08854,
telephone (201) 981-0060. Copies may be inspected during normal business
hours at RUS, room 2838-S, U.S. Department of Agriculture, Washington,
DC 20250 or at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
(10) RUS Bulletin 345-50, PE-60, RUS Specification for Trunk Carrier
Systems, September 1979, is incorporated by reference by RUS. This
incorporation by reference was approved by the Director of the Federal
Register in accordance with 5 U.S.C. 552 (a) and 1 CFR part 51. Copies
may be obtained from the Rural Utilities Service, Administrative
Services Division, room 0175-S, Washington, DC 20250. The bulletin may
be inspected at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
(11) RUS Bulletin 345-55, PE-61, Central Office Loop Extenders and
Loop Extender Voice Frequency Repeater Combinations, December 1973, is
incorporated by reference by RUS. This incorporation by reference was
approved by the Director of the Federal Register in accordance with 5
U.S.C. 552 (a) and 1 CFR part 51. Copies may be obtained from the Rural
Utilities Service, Administrative Services Division, room 0175-S,
Washington, DC 20250. The bulletin may be inspected at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700, Washington,
DC.
(12) RUS Bulletin 345-87, PE-87, RUS Specification for Terminating
(TIP) Cable, December 1983, is incorporated by reference RUS. This
incorporation by reference was approved by the Director of the Federal
Register in accordance with 5 U.S.C. 552 (a) and 1 CFR part 51. Copies
may be obtained from the Rural Utilities Service, Administrative
Services Division, room 0175-S, Washington, DC 20250. The bulletin may
be inspected at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
(b) Reliability. (1) Quality control and burn-in procedures shall be
sufficient so the failure rate of printed circuit boards does not exceed
an average of 1.0 percent per month of all equipped cards in the central
office during the first three months after cutover, and an average of
0.5 percent per month of all equipped cards in the central office during
any 6-month period thereafter. A failure is considered to be the failure
of a component on the PC board which requires it to be repaired or
replaced.
(2) The central office switching system shall be designed such that
the expected individual line downtime does not exceed 30 minutes per
year. This is the interval that the customer is out of service as a
result of all failure types, excluding dispatch and travel time, i.e.,
hardware, software, and procedural errors.
(3) The central office switching system shall be designed such that
there will be no more than 1 hour of total outages in 20 years,
excluding dispatch and travel time for unattended offices.
(c) System type acceptance tests. (1) System type acceptance tests
(general acceptance tests) are performed for the purpose of determining
whether or not a type of switching system should be added or retained as
an RUS accepted system. While general acceptance tests will be required
on each system type, they will not be expected to cover every
requirement in this section. However, any installation of a system
[[Page 599]]
provided in accordance with this section shall be capable of meeting any
requirement in this section on a spot-check basis.
(2) A ``completed call'' test shall be made part of these system
type acceptance tests. There shall be no more than two in 10,000 locally
originating and incoming calls misdirected, unsuccessfully terminated,
prematurely disconnected or otherwise failing as a result of equipment
malfunction and/or equipment failures, or as a result of transients,
noise or design deficiencies. This test shall be made with a load box
with no less than 10 lines access and 10 subscriber numbers for
completion, or equivalent, with no other traffic in the system. If there
is a failure in the equipment during this test, the cause shall be
repaired and the test restarted at zero calls.
(3) System type acceptance testing applies basically to factory type
testing, and not to owner acceptance testing for individual
installations. The overall installed and operating system shall also
meet these requirements, except for unusual circumstances or where
specifically excluded by this or other RUS requirements.
(d) Types of requirements. (1) Unless otherwise indicated, the
requirements listed in this section are fixed requirements.
(2) Optional requirements are those which may not be needed for
every office and are identifiable by a phrase such as, ``when specified
by the owner,'' or, ``as specified by the owner.''
(3) In some cases where an optional feature specified in paragraph
(e) of this section will not be required by an owner, either now or in
the future, a system which does not provide this feature will be
considered to be in compliance with this section for the specific
installation under consideration, but not in compliance with the entire
section.
(4) The owner may request bids from any RUS accepted supplier whose
system provides all the features which will be required for a specific
installation.
(5) The Application Guide, RUS TE&CM 322, provides information about
the economic and service factors involved in all optional features, as
well as instructions for the completion of appendices A and B of this
section.
(e) General requirements. (1) The equipment shall provide for
terminating and automatically interconnecting subscriber lines and
trunks in response to dial pulses (or pushbutton dialing signals, if
specified) without the aid of an operator.
(2) Complete flexibility shall be provided for assigning any
subscriber directory number to any central office line equipment by the
use of internal programmed memory. Thus, any subscriber line and/or
directory number may be moved to another terminal to distribute traffic
loads, if the line equipment hardware is compatible with the service
provided.
(3) The system shall be arranged to interface with interexchange
carrier trunks and networks using single digit or multi-digit access
codes. The system shall be equipped to handle at least 20-digit
subscriber dialed numbers. All subscriber directory numbers in the
office shall be seven-digit numbers.
(4) The network and the control equipment shall be comprised of
solid-state and integrated circuitry components. Peripheral equipment
shall be comprised of solid-state and integrated circuitry components as
far as practical and consistent with the state-of-the-art and economics
of the subject system.
(5) The basic switching system shall include the provision of
software programming and necessary hardware, including memory, for
optional custom calling services such as call waiting, call forwarding,
three-way calling, and abbreviated dialing. It shall be possible to
provide these services to any individual line (single-party) subscriber.
The addition of these services shall not reduce the anticipated ultimate
engineered line, trunk, and traffic capacity of the switching system as
specified in appendix A of this section.
(6) The requirements in this specification apply only to single
party lines. Although only single frequency ringing is required, other
types may be requested in appendix A of this section.
(7) Provision shall be made for local automatic message accounting
[[Page 600]]
(LAMA), and for traffic service position system (TSPS) trunks, or
equivalent, to the operator's office when required either initially or
in the future.
(8) Tandem switching features shall be provided if specified in
appendix A of this section.
(9) The system shall be arranged to serve a minimum of eight All
Number Calling (ANC) office codes per office, with discrimination on
terminating calls by trunk group, numbering plan, or programmed memory
and class mark, if specified in appendix A of this section.
(10) Busy hour load handling capacity is an important feature when
an office approaches capacity. The delays which may occur in call
completion during busy hour periods may prove to be excessive in some
system designs. Accordingly, each bidder shall provide, in appendix C of
this section, data satisfactory to RUS regarding the busy hour load
handling capacity and traffic delays of the system.
(11) Provision shall be made for hotel-motel arrangements, as
required by the owner, to permit the operation of message registers at
the subscriber's premises to record local outdial calls by guests (see
Item 10.5, appendix A of this section).
(12) Provision shall be made to identify the calling line or
incoming trunk on nuisance calls (see paragraph (g)(10) of this section
for details).
(13) Full access from every subscriber line to every interoffice
trunk shall be provided.
(14) Facilities shall be provided to implement service orders, make
traffic studies, and perform switching and transmission tests by means
of remote control devices if such operations are specified in Items 11.2
and 11.3 of appendix A of this section.
(15) Provision shall be made for the addition of facilities to
record all subscriber originated calls based on dialed directory number,
time of day, and duration of conversation. They shall be such that the
additional equipment (if any is required) may be added to an in-service
system without interruption of service and a minimum of equipment,
wiring and software modifications.
(16) The system shall be capable of distributed switching operation
where groups of subscriber lines can be remotely located from the
central office. The remotely situated units are known as ``Remote
Switching Terminals'' (RST's) (see paragraph (w) of this section). This
does not eliminate the use of pair gain devices such as direct digitally
connected concentrators, regular concentrators or subscriber carrier
equipment, where specifically ordered by the owner and its engineer.
(17) The switching system shall have means to synchronize its clock
with switches above it in the network hierarchy, when specified by the
owner in item 3, appendix A of this section (see paragraph (j) of this
section).
(18) Consistent with system arrangements and ease of maintenance,
space shall be provided on the floor plan for an orderly layout of
future equipment bays that will be required for anticipated traffic when
the office reaches its ultimate size. Readily accessible terminals shall
be provided for connection to interbay and frame cables to future bays.
All cables, interbay and intrabay (excluding power), if technically
feasible, shall be terminated at both ends by use of connectors.
(19) When specified in appendix A of this section, the system shall
be capable of processing emergency calls to a 911 service bureau
connected either by a group of one-way 911 lines or a trunk group.
(i) It shall be possible to reach the service bureau by dialing 911,
1+911, or a 7-digit number.
(ii) The system shall select an idle 911 line or trunk.
(iii) The system shall provide usual ringing and ringback signal
until the called 911 line answers.
(iv) If the calling line goes on-hook first, the system shall hold
the connection from the called 911 line and return steady low tone to
the service bureau. The system shall then begin a 45-minute timeout,
after which the calling line is disconnected and an alarm message is
printed on a TTY. If the calling line goes off-hook before timeout, the
system shall reestablish the conversation path.
(v) If the calling line does not disconnect, the service bureau
attendant
[[Page 601]]
shall have the ability to force a disconnect of the established
connection with the calling party.
(vi) When the 911 call is answered, the equipment shall be arranged
so that coin lines are not charged for the call. Similarly, if some form
of local call charging is used, there shall be no charge for the 911
call.
(vii) If the 911 service bureau is holding a calling line, it shall
be possible for the 911 line to cause the equipment to ring back the
calling line. This is done by providing a flash of on-hook signal from
the 911 line lasting from 200 to 1,100 milliseconds. The signal to the
calling line shall be ringing current if the line is on-hook, or
receiver off-hook (ROH) tone if the line is off-hook.
(viii) Calls shall not be originated from the service bureau via the
dedicated 911 lines. If an attempt is made to originate a call, it shall
receive reorder tone. After 6 minutes, the system shall print an alarm
message.
(ix) If 911 calls pass through intermediate switching, the forced-
hold control, emergency ringback, and calling line status monitoring
capabilities are lost.
(f) Line circuit requirements--(1) General. (i) The range of direct
current (dc) resistances of subscriber loops, measured from the main
frame in the central office and including the telephone set shall be at
least 0-1900 ohms without loop extension and 1900-3600 ohms with loop
extenders, or equivalent. The range when using extension equipment may
be significantly reduced for straight line ringers. These limits apply
under maximum adverse environmental and manufacturing variation
tolerance conditions. Central office voltage shall be stabilized at a
value necessary to provide at least a nominal 21 milliamperes current
with a nontreated loop of at least 1900 ohms. Minimum loop insulation
resistance without loop extenders shall be 25,000 ohms between
conductors or from either conductor or both conductors in parallel to
ground. Loop insulation resistance for loop extension devices may be
100,000 ohms minimum between conductors or from either conductor or both
conductors in parallel to ground.
(ii) In addition to operating on nonloaded cable pairs and
subscriber carrier, the equipment shall function properly with D-66 and
H-88 loaded cable pairs, including any provisions the equipment must
control for the purposes of proper transmission.
(2) Dialing--(i) Subscriber dial speed. The line equipment and
central office equipment (COE) in tandem shall operate satisfactorily
when used with subscriber dials having a speed of operation between
eight and twelve impulses per second and a break period of 55 to 65
percent of the total impulse period.
(ii) Subscriber dial interdigital time. The line equipment and
central office equipment shall operate satisfactorily with subscriber
rotary dial interdigital times of 200 milliseconds minimum, and with
pushbutton dialing interdigital times of 50 milliseconds minimum.
(iii) Subscriber line pushbutton dialing frequencies. (A) The
frequency pairs assigned for pushbutton dialing shall be as follows,
with an allowable variation of 1.5 percent:
------------------------------------------------------------------------
High Group Frequencies (Hz)
Low Group Frequencies (Hz) --------------------------------------
1209 1336 1477 1633
------------------------------------------------------------------------
697.............................. 1 2 3 Spare
770.............................. 4 5 6 Spare
852.............................. 7 8 9 Spare
941.............................. * 0 0.5 seconds.
Loss of synchronization shall be detected by slips, timing jitter, and
wander in accordance with industry standards.
(iii) Signaling shall be by means of MF or dial pulse (DP) and the
system which is inherent in the A and B bits of the D3 format. In the
case where they are not used for signaling, the A and B bits shall be
used only for normal voice and data transmission.
(i) Tone requirements--(1) General. Tones shall be provided to
indicate the progress of a call through the office. Tone generators
should be an integral part of the switching systems. The tones should be
introduced digitally by the application of the appropriate bit stream to
the line or trunk circuit via the digital switching network. The
necessary precautions shall be made to ensure tone sources automatically
if the primary sources fail.
(2) Tone specifications. (i) Dial tone shall consist of 350 Hz plus
440 Hz at a composite level of -10 dBm0 which equates to -13 dBm0 per
frequency. This is the precise tone suitable for use with pushbutton
dialing.
(ii) Low tone shall consist of 480 Hz plus 620 Hz at a composite
level of -21 dBm0 which equates to -24 dBm0 per frequency.
(iii) Line busy tone shall be low tone interrupted at 60 IPM, with
tone on 0.5 seconds and off 0.5 seconds.
(iv) Reorder, all paths busy, and no circuit tone shall be low tone
interrupted at 120 IPM, with tone on 0.25 seconds and off 0.25 seconds.
(v) Identifying tone on calls from coin lines shall be uninterrupted
low tone.
(vi) High tone shall consist of 480 Hz at -17 dBm0.
(vii) Audible ringback tone shall consist of 440 plus 480 Hz at a
composite level of -16 dBm0 which equates to -19 dBm0 per frequency.
(viii) The call progress tones listed in this section are described
in Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks--1990,
section 6. The 350, 440, 480, and 620 Hz tones shall be held at
0.5 percent frequency tolerance and 3 dB
amplitude variation. The amplitude levels specified are to be measured
at the main distributing frame, excluding cable loss.
(ix) Distinctive tone, when required for alarm calls, or other
features, shall consist of high tone interrupted at 200 IPM with tone on
150 ms and off 150 ms.
(x) Identifying tone on intercepted calls shall consist of
uninterrupted high tone impressed on the trunk circuit 300 to 600
milliseconds following the operator's answer of intercepted calls.
(xi) An ROH circuit shall have output tones which do not interfere
with the pushbutton or multifrequency signaling tones. The ROH tone may
be introduced digitally internal to the system near the overload level
of +3 dBm0. No power adjustment will be required. The frequency of the
output shall be distinctive and urgent in order to attract the
subscriber's attention to an off-hook situation. (Warning: In order to
determine the signal level, a frequency selective voltmeter must be used
to determine the level of each signal component and mathematical power
addition used to combine these measurements into a single level value.)
(xii) During application of tones, office longitudinal balance shall
be maintained within 15 dB of that specified in paragraph (q)(8) of this
section.
(j) System clock. (1) The central office clock and network
synchronization system shall have the ability to be synchronized with
external clocks for network synchronization, including detection of
slips, timing, jitter and wander,
[[Page 607]]
in a digital-to-digital environment or operate initially in an
independent network (refer to Bellcore document SR-TSV-002275, BOC Notes
on the LEC Networks--1990, section 11).
(2) The end office central office system clock shall be a Stratum 3
clock with:
(i) A minimum long-term accuracy of 4.6 x
10-6 (7 Hz @ 1.544 MHz);
(ii) A minimum stability of 3.7 x 10-7/day upon loss of
all frequency references; and
(iii) A ``Pull-In Range'' for the capability of synchronizing to a
clock with accuracy of 4.6 x 10 -6.
(3) The access tandem central office system clock shall be a Stratum
2 clock with:
(i) A minimum long-term accuracy of 1.6 x
10-8 (0.025 Hz @ 1.544 MHz);
(ii) A minimum stability of 1 x 10-10/day upon loss of
all frequency references; and
(iii) A ``Pull-In Range'' for the capability of synchronization to a
clock with accuracy of 1.6 x 10-8.
(k) Switched access service arrangements--(1) General. The equipment
shall be capable of providing Feature Group A, Feature Group B, Feature
Group C, and Feature Group D switched access service arrangements, as
described in Bellcore document SR-TSV-002275, BOC Notes on the LEC
Networks--1990, section 6 and section 15, including arrangements for
automatic number identification (ANI).
(2) Operation. (i) All equipment shall be arranged for Feature Group
A (Line Side Connection).
(ii) All equipment shall be arranged for Feature Group B given that
appendix A of this section requires the equipment of the necessary
trunks (Trunk Side Connection).
(iii) The equipment shall be arranged for Feature Group C on the
trunk groups specified in appendix A of this section. Even though
appendix A of this section specifies Feature Group D or some other trunk
group, it shall be possible through software commands available to the
owner to use Feature Group C signaling protocols on a trunk group basis
until such time that the trunk group in question converts to Feature
Group D signaling protocols.
(iv) The equipment shall be arranged for Feature Group D on the
trunk groups specified in appendix A of this section.
(v) Calls originating from coin lines toward switched access service
shall be arranged either to provide signaling protocols for TSPS, or in
the absence of TSPS-type service, such calls shall be blocked.
(vi) The equipment shall be arranged for forwarding routing
information, calling party identification, and called party numbers in
the proper feature group protocols, by trunk group as specified in
appendix A of this section.
(vii) The equipment shall be arranged for AMA data collection as
specified in appendix A of this section by trunk group. Unless otherwise
specified by the owner, the equipment shall be arranged to collect the
billing data in the Bellcore AMA format as described in Bellcore
document TR-TSY-000508, Automatic Message Accounting.
(viii) If specified in Item 9.4, appendix A of this section, the
equipment shall be arranged to store the billing data in a pollable
system. If specified in Item 9.5, appendix A of this section, equipment
shall be furnished to poll the pollable systems associated with the
contract.
(l) Fusing and protection requirements--(1) General. (i) The
equipment shall be completely wired and equipped with fuses, trouble
signals, and arranged for printout of fault conditions, with all
associated equipment for the wired capacity of the frames or cabinets
provided.
(ii) Design precautions shall be taken to prevent the possibility of
equipment damage arising from the insertion of an electronic package
into the wrong connector, the removal of a package from any connector,
or the improper insertion of the correct card in its connector.
(2) Fuses. Fuses and circuit breakers shall be of an alarm and
indicator type, except where the fuses or breaker location is indicated
on the alarm printout. Their rating shall be designated by numerals or
color code on the fuse panel, where feasible.
(3) Components. (i) Insofar as possible, all components shall be
capable of being continuously energized at rated
[[Page 608]]
voltage without injurious results. Insofar as possible, design
precautions shall be taken to prevent damage to other equipment and
components when a particular component fails.
(ii) Printed circuit boards or similar equipment employing
electronic components shall be self-protecting against external grounds
applied to the connector terminals, where feasible. Board components and
coatings applied to finished products shall be of such material or
treated so they will not support combustion.
(iii) Every precaution shall be taken to protect electrostatically
sensitive components from damage during handling. This shall include
written instructions and recommendations (see Item 6.1,h of appendix C
of this section).
(m) Switching network requirements--(1) The network. (i) All
networks shall be comprised of solid-state components.
(ii) The switching network shall employ time division digital
switching and be compatible for connection to D3 type PCM channel banks
without conversion to analog.
(iii) Equipment shall be available as required to connect analog
lines and trunks, analog or digital service circuits, digital carriers
to RST's, D3 channel banks or other digital switching units.
(2) Network quantity. Where the number of stages in the switching
network and their control varies with the capacity of the system,
sufficient equipment and wiring shall be supplied initially in order
that there will be no service interruptions when additions are made up
to the ultimate capacity as specified in appendix A of this section.
This does not imply the necessity of supplying empty cabinets unless
this is the only way the necessary wiring can be accomplished.
(n) Stored program control (SPC) equipment requirements. (1) The
system shall provide redundancy in call processing such that the failure
of a call processing unit does not degrade the call processing
capabilities of the switching system nor result in the loss of
established calls.
(2) Programs shall be modular, flexible and structured. In the
interest of more dependable and more easily read programs, it is
desirable to use a language which is more person-oriented leaving the
detailed machine-oriented problems to a compiler program. Quality
assurance of all software programs shall be in accordance with IEEE Std
730-1989, IEEE Standard for Software Quality Assurance Plans, or
equivalent.
(3) The office administration program shall have checks within it to
prevent failure due to erroneous or inconsistent input data. It shall
safeguard against the possibility of upsetting machine performance with
improper instructions or information. In addition, modular structure
shall allow the use of a variety of human-engineered service order
formats. Service changes may be performed remotely if so desired.
Average machine time for service change shall be 15 seconds or less.
Service changes shall not be registered in permanent memory until
verified. The access to the service change shall not have access to
generic program.
(4) The switching system shall be able to offer, by request, at
least the following printouts of its routine stored data for
administrative purposes:
(i) A list of all assigned directory numbers, in numerical order,
with their assigned class of service and line terminal numbers;
(ii) A list of all directory numbers, in numerical order, associated
with a class of service;
(iii) A list of all unassigned line terminals;
(iv) Traffic data in proper form for separation studies in
accordance with the revenue separations procedures current at the time
of the contract;
(v) All lines on lockout;
(vi) All lines assigned to intercept;
(vii) All available (unassigned) directory numbers in the working
thousands group; and
(viii) A list of equipment busied out for maintenance.
(5) The printouts in paragraph (n)(4) of this section may be delayed
to times of light traffic.
[[Page 609]]
(6) Maintenance diagnostics shall be performed by a fault
recognition system utilizing both software and hardware, each being used
where they are most effective for maintenance and reliability. In the
economic interests of providing early and efficient fault detection and
accurate pinpointing of faulty areas, it is desirable to have a
comprehensive person-machine interface supported by extensive automatic
fault detection and analysis, involving diagnostic software for fault
resolution and automatic recovery mechanisms to maintain continuous
service. Maintenance messages may be channeled to a remote maintenance
center if so desired.
(7) Information in memory, having no requirement for changes to be
introduced in the maintenance or operation of the system, may be stored
in memory devices such as programmable read-only memory (PROM) or other
devices that cannot be reprogrammed in the field.
(o) Maintenance facilities--(1) Alarm features, including alarm
sending. (i) The equipment shall be arranged to provide audible and
visual alarms indicating fuse operation or other circuit malfunctions
resulting from component failure, crosses or open wiring, or any other
conditions affecting service which can be detected economically.
(ii) The alarms shall be classified in accordance with their effect
on the system.
(A) Catastrophic alarms demand immediate attention and require
notification of the highest level of supervisory personnel. Conditions
such as loss of service, loss of one or more remote line switches or
line concentrators connected through Direct Digital Interface, loss of
network control, and loss of computer program in all processors shall
produce catastrophic alarms.
(B) Major alarms demand rapid action. Conditions such as loss of one
or more groups of subscribers or trunk ports, blown fuses for common
groups of channels, loss of control to groups of channels, failure of
one or both redundant units, and total loss of battery charging current
for more than 15 minutes shall produce major alarms.
(C) Minor alarms indicate nonemergency conditions which cause
degraded service or fault conditions which causes the system to operate
within less-than-optimum performance. Conditions discovered in automatic
routining which have not shown in the operation of the equipment but
require attention and cumulative line lockout (level adjustable) are
examples of minor alarm conditions.
(iii) When the office is arranged for unattended operation,
facilities shall be provided for extending the alarm indications to an
attended point.
(iv) When the use of a separate outside plant facility for alarm
sending is specified, the nature of the alarm may be indicated to the
distant point by machine printout or other display device.
(v) When alarm sending is accomplished over a regular operator
office trunk, the operator shall be apprised that the call is an alarm
indication by a distinctive tone, as specified by the owner in appendix
A of this section. It shall be possible for the operator to determine at
any time the presence of a trouble condition by dialing a number set
aside for that purpose. This number shall also be accessible from lines
classmarked for this feature.
(vi) When the alarm sending circuit seizes an interoffice operator
trunk, the operator must dial the alarm checking code over another trunk
before the first trunk can be released except where the alarm condition
has disappeared first.
(vii) The alarm sending circuit shall have access to two or more
trunks if the trunks are used for subscriber traffic.
(viii) An alarm indication of higher priority shall supersede an
original alarm indication and reseize an interoffice operator trunk.
(ix) In any group of offices purchased under one contract, the same
codes shall be used in each office for alarm checking and test.
(x) When the alarm checking number is dialed, the alarm indications
received shall be as follows:
(A) Catastrophic alarm--No tone.
(B) Major alarm--Continuous busy tone 60 IPM, unless alarm is
overridden.
[[Page 610]]
(C) Minor alarm--Continuous 1-ring code ringback tone, unless alarm
is overridden.
(D) No trouble--Continuous 2-ring code ringback tone, unless alarm
is overridden.
(xi) Audible and visual local alarms and transmitted alarms shall be
provided as follows:
------------------------------------------------------------------------
Delay Interval
------------------------------------------------------------------------
Local
Classification Alarms Alarms Transmitted
------------------------------------------------------------------------
Catastrophic 0 0
Major 0 0\1\
Minor 0 0-30 Min.
------------------------------------------------------------------------
\1\Except no charge alarm delayed 15 minutes.
(xii) The central office alarm circuits shall be arranged to provide
optional wiring to transmit either a minor alarm or a major alarm and a
printout to accommodate various types of trunk and subscriber carrier
systems, microwave, mobile radio, other transmission systems, and
environmental protection systems with different priorities when a set of
contacts is closed in the equipment of such systems and the alarm
checking code is dialed. The alarm relay shall be furnished by the
supplier of the carrier multiplex and/or mobile radio equipment. The
option or options shall be specified by the owner.
(2) Trouble location and test. (i) Equipment. (A) A maintenance
center shall be provided with a fault recorder (printer and/or display)
for troubles. Here, system and sub-system visual trouble indications are
shown for maintenance aid.
(B) The fault recorder shall provide a permanent or semi-permanent
record of the circuit elements involved whenever a trouble is
encountered. It shall be arranged to recognize an existing fault
condition and not cause multiple printouts of the same fault, except
during test routine.
(ii) Maintenance system. (A) The maintenance system shall monitor
and maintain the system operation without interruption of call
processing, except for major failures.
(B) The maintenance system shall provide both specialized
maintenance hardware circuits and an extensive software package to
enable maintenance to determine trouble to an individual card or
functional group of cards.
(C) Maintenance programs may be both on-line and off-line. On-line
maintenance programs are activated by system errors and shall be
scheduled to execute call tests during low traffic periods and periodic
hardware tests at specific time intervals. Programs shall provide
diagnostic tools for the maintenance personnel and be initiated by them.
(D) Scheduled periodic hardware tests shall automatically detect
faults and alert maintenance personnel via alarm or appropriate input/
output device(s) at local and/or remote locations.
(E) Facilities shall be provided so that test calls can be set up
using pre-selected items of switching equipment.
(F) The maintenance personnel shall be able to make tests to
determine if every trunk and every item of switching equipment are
functioning properly. Also, it shall be possible to make each trunk and
each SPC equipment, or part thereof, busy to service calls. Where
possible, equipment which is made busy to service calls shall still be
accessible for test calls.
(iii) Outside plant and subscriber stations. (A) A subscriber loop
test set or equivalent shall be provided either as a separate set or as
a part of the maintenance center, as specified in item 11.2 of appendix
A of this section. This circuit shall include a high resistance volt-ohm
meter, wiring to tip and ring terminals to permit a portable wheatstone
bridge to be used, an operator's telephone circuit, a dial circuit (and
pushbutton dialing keys, if specified), outgoing trunks to dial
equipment for access to lines under test without use of the main
distributing frame (MDF) test shoe and the necessary test keys. No dry
cell batteries shall be accepted for test potentials. Circuits shall be
designed so that alternating current (ac) induction on the line will
have no effect on dc measurements. All functions shall be under control
of lever or pushbutton keys. As a minimum the test system shall:
(1) Test for bridged foreign electromotive force (EMF);
(2) Test for regular line battery;
[[Page 611]]
(3) Test for booster battery voltage and polarity using the test
shoe;
(4) Test for open circuits, short, tip ground, and ring ground;
(5) Test for tip or ring negative potential;
(6) Test for capacitance of a subscriber's line;
(7) Supply talking battery to the line with and without booster
battery;
(8) Ring the subscriber through the test access circuit or through a
test shoe;
(9) Test in and out of the central office; and
(10) Supply a reverse polarity key for voltage readings, except when
positive or negative values are displayed directly.
(B) An acceptable arrangement for making the tests shown in
paragraph (o)(2)(iii)(A) of this section is to have them under software
control with results displayed at one of the system's I/O ports.
(C) A howler circuit for maintenance purposes, if ordered by the
owner, shall have output tones which do not interfere with the
pushbutton or multifrequency signaling tones. The harmonics of the
output tones shall be attenuated at least 26 dB below the fundamental
frequency for all load conditions. The frequency stability shall be 2
percent or less for all output tones when the unit is operated in the
specified load and environmental range. It shall be possible to vary the
output voltage (power) of the howler circuit. It shall remove tone and
restore the line to service when the telephone instrument receiver is
placed on-hook. The frequency of the output shall be chosen to be
distinctive and urgent in order to attract the subscriber's attention to
an off-hook situation.
(D) When a dial speed test facility is specified by the owner, it
shall be accessed by dialing a special code and shall return to the
calling station readily identifiable signals to indicate that the dial
speed is slow, normal, or fast.
(E) When the office is arranged for pushbutton dialing, optional
facilities shall be provided for testing the pushbutton dialing
equipment at the subscriber station.
(F) When a system for testing subscriber lines in remote offices
from a test position in a centrally located office is specified by the
owner, it shall be capable of working with all the central offices and
RST's in the remote areas. This testing equipment shall preferably be
solid-state with a minimum of electromechanical devices and shall
operate from central office battery. It shall be capable of working over
any voice grade telephone circuit and shall not require a dedicated
trunk. There shall be no interference to or from ``in-band'' voice
channel tones. When used over a network, the verification or access
shall be guarded to prevent unauthorized access by subscribers. Access
to this system shall only be available to the test operator in all
cases.
(3) Transmission testing. (i) When transmission test circuits are
specified in Item 11.3 of appendix A of this section, they shall permit
testing of trunks by a distant office without any assistance in the
local dial office. Analog test ports shall meet appropriate trunk
requirements. If Centralized Automatic Reporting on Trunks (CAROT), or
equivalent, is to be used, the equipment at the end office shall comply
with Bellcore document SR-TSV-002275, BOC Notes on the LEC Networks--
1990, section 8, Item 2.
(ii) Transmission test circuits are available with a variety of
options. These include single frequency and multifrequency tone
generators with one or more generator output terminals, quiet
terminations, and loop around test arrangements for both one-way and
two-way trunks.
(iii) Where multifrequency generators are used, they are usually
arranged to provide a minimum of three frequencies. With some equipment,
up to seven additional frequencies may be provided if needed. No
industry standardization of test frequencies is as yet provided.
Therefore, it is important that the selection of frequencies, the order
in which they are applied and the time interval for application of each
frequency be agreed upon by the connecting company and the RUS borrower
and listed in appendix A of this section in those situations where
connecting companies request the installation of multifrequency
generators in borrowers' central offices.
[[Page 612]]
(iv) The milliwatt generator shall be solid-state and generate the
analog or digital equivalent of 1004 Hz. The milliwatt generator shall
be assigned to a 4-wire analog test port or be digitally generated. All
2-wire and 4-wire voice frequency ports are at a nominal 0 dBm0 level.
The level of the 1004 Hz tone generator shall appear at outgoing 2-wire
and 4-wire ports at 0 dBm 0.5 dB. For direct digital
connections, the encoded output shall be the digital equivalent of a 0
dBm0 0.5 dB signal.
(v) Reference tone generators can be used individually or they can
be part of a loop around test arrangement. If both single frequency and
multifrequency reference tone generators are to be provided, only one
can be arranged as part of a loop around test. Where a loop around
arrangement is provided, the generator output can be obtained by dialing
singly one of the two line terminals. By dialing the other line terminal
singly, usually a 900 ohm resistor in series with a 2.16 microfarad
capacitor is connected to the circuit under test to act as a ``quiet
termination'' for noise measurements and other tests. Whenever both line
terminals are held simultaneously, both the milliwatt supply and the
quiet termination shall be lifted off and a ``loop around'' condition
established. This permits the overall loss to be determined from the
distant office by going out over one trunk, looping around in the end
office and returning over the other trunk. The insertion loss of this
test arrangement when used in a loop around configuration should not
exceed 0.1 dB at the frequencies specified for the milliwatt supply.
Unless otherwise specified, continuous off-hook supervision is to be
provided on both line terminals to prevent collusive calling without
charge. It will be permissible to accomplish the quiet termination by
opening the 4-wire path internally and to accomplish the loop around by
digital switching.
(vi) Provision shall be made so that the milliwatt supply can be
manually patched to circuits.
(vii) Test jack access shall be provided for all interoffice trunks
of the voice frequency type. The jack access shall be properly
designated for line, drop, monitor, and signaling leads plus any other
jacks as requested by the owner. This may be accomplished by a set of
jacks located at the maintenance center which have access to each trunk
on a switching basis.
(p) Traffic--(1) General engineering guidelines. (i) The Traffic
Table, based on the Erlang Lost-Calls-Cleared Formula, shall be used for
determining the quantity of intraoffice paths, registers, and senders
where full availability conditions apply. The following table shows the
traffic capacity in CCS for 1 to 200 trunks at nine grades of service.
Traffic Table
Full Availability for Random Traffic
Lost-Calls-Cleared
Offered Traffic Expressed in CCS
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Number of
Trunks B-.001 .002 .005 .01 .02 .05 .1 .2 .5 Number of Trunks
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 0................ 0............... 0............... 0............... 1............... 2............... 4............... 9............... 36.............. 1
2 2................ 3............... 4............... 5............... 8............... 14.............. 22.............. 36.............. 98.............. 2
3 7................ 9............... 13.............. 17.............. 22.............. 32.............. 46.............. 69.............. 165............. 3
4 16............... 19.............. 25.............. 31.............. 39.............. 55.............. 74.............. 106............. 234............. 4
5 27............... 32.............. 41.............. 49.............. 60.............. 80.............. 104............. 144............. 304............. 5
6 41............... 48.............. 58.............. 69.............. 82.............. 107............. 135............. 184............. 374............. 6
7 57............... 65.............. 78.............. 90.............. 106............. 135............. 168............. 224............. 445............. 7
8 74............... 83.............. 98.............. 113............. 131............. 163............. 202............. 265............. 516............. 8
9 92............... 103............. 120............. 136............. 156............. 193............. 236............. 307............. 586............. 9
10 111.............. 123............. 143............. 161............. 183............. 224............. 270............. 348............. 656............. 10
11 131.............. 145............. 166............. 186............. 210............. 255............. 306............. 391............. 729............. 11
12 152.............. 167............. 190............. 212............. 238............. 286............. 341............. 433............. 801............. 12
13 174.............. 190............. 215............. 238............. 266............. 318............. 377............. 476............. 872............. 13
14 196.............. 213............. 240............. 265............. 295............. 350............. 413............. 519............. 944............. 14
15 219.............. 237............. 266............. 292............. 324............. 383............. 449............. 562............. 1015............ 15
16 242.............. 261............. 292............. 320............. 354............. 415............. 486............. 605............. 1087............ 16
17 266.............. 286............. 318............. 347............. 384............. 449............. 523............. 648............. 1158............ 17
18 290.............. 311............. 345............. 376............. 414............. 482............. 560............. 692............. 1230............ 18
[[Page 613]]
19 314.............. 337............. 372............. 404............. 444............. 515............. 597............. 735............. 1302............ 19
20 339.............. 363............. 399............. 433............. 474............. 549............. 634............. 779............. 1374............ 20
21 364.............. 388............. 427............. 462............. 505............. 583............. 671............. 823............. 1445............ 21
22 389.............. 415............. 455............. 491............. 536............. 617............. 709............. 866............. 1517............ 22
23 415.............. 441............. 483............. 521............. 567............. 651............. 747............. 910............. 1589............ 23
24 441.............. 468............. 511............. 551............. 599............. 685............. 784............. 954............. 1661............ 24
25 467.............. 495............. 540............. 580............. 630............. 720............. 822............. 998............. 1733............ 25
26 493.............. 523............. 568............. 611............. 662............. 754............. 860............. 1042............ 1805............ 26
27 520.............. 550............. 598............. 641............. 693............. 788............. 898............. 1086............ 1876............ 27
28 546.............. 578............. 627............. 671............. 725............. 823............. 936............. 1130............ 1948............ 28
29 573.............. 606............. 656............. 702............. 757............. 858............. 974............. 1174............ 2020............ 29
30 600.............. 634............. 685............. 732............. 789............. 893............. 1012............ 1218............ 2092............ 30
31 628.............. 662............. 715............. 763............. 822............. 928............. 1050............ 1263............ 2164............ 31
32 655.............. 690............. 744............. 794............. 854............. 963............. 1089............ 1307............ 2236............ 32
33 683.............. 719............. 774............. 825............. 887............. 998............. 1127............ 1351............ 2308............ 33
34 711.............. 747............. 804............. 856............. 919............. 1033............ 1165............ 1395............ 2380............ 34
35 739.............. 776............. 834............. 887............. 951............. 1068............ 1203............ 1439............ 2452............ 35
36 767.............. 805............. 864............. 918............. 984............. 1104............ 1242............ 1484............ 2524............ 36
37 795.............. 834............. 895............. 950............. 1017............ 1139............ 1281............ 1528............ 2595............ 37
38 823.............. 863............. 925............. 981............. 1050............ 1174............ 1319............ 1572............ 2667............ 38
39 851.............. 892............. 955............. 1013............ 1083............ 1210............ 1358............ 1617............ 2739............ 39
40 880.............. 922............. 986............. 1044............ 1116............ 1246............ 1396............ 1661............ 2811............ 40
41 909.............. 951............. 1016............ 1076............ 1149............ 1281............ 1435............ 1706............ 2883............ 41
42 937.............. 980............. 1047............ 1108............ 1182............ 1317............ 1474............ 1750............ 2955............ 42
43 966.............. 1010............ 1078............ 1140............ 1215............ 1352............ 1512............ 1795............ 3027............ 43
44 995.............. 1040............ 1109............ 1171............ 1248............ 1388............ 1551............ 1839............ 3099............ 44
45 1024............. 1070............ 1140............ 1203............ 1282............ 1424............ 1590............ 1884............ 3171............ 45
46 1053............. 1099............ 1171............ 1236............ 1315............ 1459............ 1629............ 1928............ 3243............ 46
47 1083............. 1129............ 1202............ 1268............ 1349............ 1495............ 1668............ 1973............ 3315............ 47
48 1112............. 1159............ 1233............ 1300............ 1382............ 1531............ 1706............ 2017............ 3387............ 48
49 1141............. 1189............ 1264............ 1332............ 1416............ 1567............ 1745............ 2062............ 3459............ 49
50 1170............. 1220............ 1295............ 1364............ 1449............ 1603............ 1784............ 2106............ 3531............ 50
51 1200............. 1250............ 1327............ 1397............ 1483............ 1639............ 1823............ 2151............ 3603............ 51
52 1229............. 1280............ 1358............ 1429............ 1516............ 1675............ 1862............ 2195............ 3675............ 52
53 1259............. 1310............ 1390............ 1462............ 1550............ 1711............ 1901............ 2240............ 3747............ 53
54 1289............. 1341............ 1421............ 1494............ 1584............ 1747............ 1940............ 2285............ 3819............ 54
55 1319............. 1371............ 1453............ 1527............ 1618............ 1783............ 1979............ 2329............ 3891............ 55
56 1349............. 1402............ 1484............ 1559............ 1652............ 1819............ 2018............ 2374............ 3962............ 56
57 1378............. 1432............ 1516............ 1592............ 1686............ 1856............ 2057............ 2418............ 4034............ 57
58 1408............. 1463............ 1548............ 1625............ 1719............ 1892............ 2096............ 2463............ 4106............ 58
59 1439............. 1494............ 1579............ 1657............ 1753............ 1928............ 2136............ 2508............ 4178............ 59
60 1468............. 1525............ 1611............ 1690............ 1787............ 1965............ 2174............ 2552............ 4250............ 60
61 1499............. 1556............ 1643............ 1723............ 1821............ 2001............ 2214............ 2597............ 4322............ 61
62 1529............. 1587............ 1675............ 1756............ 1855............ 2037............ 2253............ 2642............ 4394............ 62
63 1559............. 1617............ 1707............ 1789............ 1889............ 2073............ 2292............ 2687............ 4466............ 63
64 1590............. 1648............ 1739............ 1822............ 1923............ 2110............ 2331............ 2731............ 4538............ 64
65 1620............. 1679............ 1771............ 1855............ 1958............ 2146............ 2370............ 2776............ 4610............ 65
66 1650............. 1710............ 1803............ 1888............ 1992............ 2182............ 2409............ 2821............ 4682............ 66
67 1681............. 1742............ 1835............ 1921............ 2026............ 2219............ 2449............ 2865............ 4754............ 67
68 1711............. 1773............ 1867............ 1954............ 2060............ 2255............ 2488............ 2910............ 4826............ 68
69 1742............. 1804............ 1900............ 1987............ 2094............ 2291............ 2527............ 2955............ 4898............ 69
70 1773............. 1835............ 1932............ 2020............ 2129............ 2328............ 2566............ 3000............ 4970............ 70
71 1803............. 1867............ 1964............ 2053............ 2163............ 2364............ 2606............ 3044............ 5042............ 71
72 1834............. 1898............ 1997............ 2087............ 2197............ 2401............ 2645............ 3089............ 5114............ 72
73 1865............. 1929............ 2029............ 2120............ 2232............ 2438............ 2684............ 3134............ 5186............ 73
74 1895............. 1961............ 2061............ 2153............ 2266............ 2474............ 2723............ 3178............ 5258............ 74
75 1926............. 1992............ 2093............ 2186............ 2300............ 2511............ 2763............ 3223............ 5330............ 75
76 1957............. 2024............ 2126............ 2219............ 2335............ 2547............ 2802............ 3268............ 5402............ 76
77 1988............. 2055............ 2159............ 2253............ 2369............ 2584............ 2841............ 3313............ 5474............ 77
78 2019............. 2087............ 2191............ 2286............ 2404............ 2620............ 2881............ 3357............ 5546............ 78
79 2050............. 2118............ 2223............ 2319............ 2438............ 2657............ 2920............ 3402............ 5618............ 79
[[Page 614]]
80 2081............. 2150............ 2256............ 2353............ 2473............ 2694............ 2959............ 3447............ 5690............ 80
81 2112............. 2182............ 2289............ 2386............ 2507............ 2730............ 2999............ 3492............ 5762............ 81
82 2143............. 2213............ 2321............ 2420............ 2542............ 2767............ 3038............ 3537............ 5834............ 82
83 2174............. 2245............ 2354............ 2453............ 2577............ 2803............ 3077............ 3581............ 5906............ 83
84 2206............. 2277............ 2386............ 2487............ 2611............ 2840............ 3117............ 3626............ 5977............ 84
85 2237............. 2309............ 2419............ 2521............ 2646............ 2877............ 3156............ 3671............ 6049............ 85
86 2268............. 2340............ 2452............ 2554............ 2680............ 2913............ 3196............ 3716............ 6121............ 86
87 2299............. 2372............ 2485............ 2588............ 2715............ 2950............ 3235............ 3761............ 6193............ 87
88 2331............. 2404............ 2517............ 2621............ 2750............ 2987............ 3275............ 3805............ 6265............ 88
89 2362............. 2436............ 2550............ 2655............ 2784............ 3024............ 3314............ 3850............ 6337............ 89
90 2393............. 2468............ 2583............ 2688............ 2819............ 3060............ 3353............ 3895............ 6409............ 90
91 2425............. 2500............ 2616............ 2722............ 2854............ 3097............ 3393............ 3940............ 6481............ 91
92 2456............. 2532............ 2649............ 2756............ 2889............ 3134............ 3432............ 3984............ 6553............ 92
93 2488............. 2564............ 2682............ 2790............ 2923............ 3171............ 3471............ 4029............ 6625............ 93
94 2519............. 2596............ 2715............ 2823............ 2958............ 3208............ 3511............ 4074............ 6697............ 94
95 2551............. 2628............ 2748............ 2857............ 2993............ 3244............ 3551............ 4119............ 6769............ 95
96 2582............. 2660............ 2781............ 2891............ 3028............ 3281............ 3590............ 4164............ 6841............ 96
97 2614............. 2692............ 2814............ 2925............ 3063............ 3318............ 3630............ 4209............ 6913............ 97
98 2645............. 2724............ 2847............ 2958............ 3097............ 3355............ 3669............ 4253............ 6985............ 98
99 2677............. 2757............ 2880............ 2992............ 3132............ 3392............ 3708............ 4298............ 7057............ 99
100 2709............. 2789............ 2913............ 3026............ 3167............ 3429............ 3748............ 4343............ 7129............ 100
105 2867............. 2950............ 3078............ 3196............ 3342............ 3613............ 3946............ 4567............ 7489............ 105
110 3027............. 3112............ 3244............ 3366............ 3516............ 3798............ 4143............ 4792............ 7849............ 110
115 3186............. 3275............ 3411............ 3536............ 3691............ 3983............ 4341............ 5016............ 8209............ 115
120 3347............. 3437............ 3578............ 3707............ 3867............ 4168............ 4539............ 5241............ 8569............ 120
125 3507............. 3601............ 3745............ 3878............ 4043............ 4353............ 4737............ 5465............ 8929............ 125
130 3669............. 3765............ 3912............ 4049............ 4219............ 4539............ 4935............ 5689............ 9289............ 130
135 3830............. 3929............ 4081............ 4221............ 4395............ 4724............ 5133............ 5914............ 9649............ 135
140 3992............. 4093............ 4249............ 4392............ 4571............ 4910............ 5332............ 6138............ 10009........... 140
145 4155............. 4258............ 4418............ 4564............ 4748............ 5095............ 5530............ 6363............ 10369........... 145
150 4318............. 4423............ 4586............ 4737............ 4925............ 5282............ 5728............ 6587............ 10729........... 150
155 4481............. 4589............ 4755............ 4909............ 5102............ 5467............ 5927............ 6812............ 11089........... 155
160 4644............. 4755............ 4925............ 5082............ 5279............ 5654............ 6125............ 7037............ 11449........... 160
165 4808............. 4920............ 5094............ 5255............ 5457............ 5840............ 6324............ 7261............ 11809........... 165
170 4972............. 5087............ 5264............ 5428............ 5634............ 6026............ 6523............ 7486............ 12169........... 170
175 5137............. 5253............ 5434............ 5602............ 5811............ 6213............ 6722............ 7710............ 12529........... 175
180 5301............. 5420............ 5604............ 5775............ 5989............ 6399............ 6920............ 7935............ 12889........... 180
185 5466............. 5587............ 5775............ 5949............ 6167............ 6586............ 7119............ 8160............ 13249........... 185
190 5631............. 5754............ 5945............ 6123............ 6345............ 6773............ 7318............ 8384............ 13609........... 190
195 5797............. 5922............ 6116............ 6296............ 6524............ 6960............ 7517............ 8609............ 13969........... 195
200 5962............. 6089............ 6287............ 6471............ 6702............ 7146............ 7716............ 8834............ 14329........... 200
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
(ii) The traffic capacity for all interoffice trunks shall be based
on full availability, even though the distant office itself is not
engineered to provide full availability access.
(iii) The Traffic Table may also be used to determine the
approximate traffic capacity of high-usage intertoll trunks. The traffic
offered to high-usage groups may be read at B.10, signifying that 10
percent of the traffic overflows to the alternate route. This
approximates the HU12 table used by AT&T.
(iv) In reading the trunk quantity from the table, the higher
quantity shall be used when the CCS load is three or more CCS over the
lower quantity. For example, the number of trunks justified for 294 CCS
at B.005 is 16, but for 295 CCS 17 trunks are justified.
(v) Limited availability is not permitted.
(vi) The traffic capacity in the following table should be used for
small trunk groups such as pay station, special service trunks,
intercept, and PBX
[[Page 615]]
trunks, unless otherwise specified in appendix A of this section:
------------------------------------------------------------------------
Number of Circuits Permissible CCS
------------------------------------------------------------------------
1 10
2 20
3 30
4 40
------------------------------------------------------------------------
(vii) The percentage of lines equipped for pushbutton dialing is to
be used to determine the number of tone receivers. Local registers, if
required, shall be supplied on the basis of all dial pulse.
(2) Grade of service. (i) Grade of service specifies the expected
performance when there are adequate service facilities for an assumed
volume of traffic. It is expressed as a portion of the total traffic
during a busy hour that cannot be terminated immediately or within a
predetermined time period due to congestion. This places responsibility
on the traffic engineers to specify facilities which will be entirely
satisfactory to the users and which can be equipped at a price which
will be accepted as reasonable.
(ii) The number of calls encountering dial tone delay in excess of 3
seconds, measured over the busy hour of the four high-consecutive week
(4HW) period, shall not be more than 1.5 percent.
(iii) The average post dialing delay objective for an intraoffice
call shall not exceed 1 second. This includes all connect, operate, and
translation time.
(iv) The line to line (intraoffice) network matching loss objective
shall be 0.02 or less.
(v) The blocking probabilities related to trunks include both
``mismatch'' probability and probability of ``all trunks busy.'' It is
likely that the ``mismatch'' will be negligible in that many digital
central offices have essentially nonblocking switching characteristics.
The objectives for trunk connections are as follows:
(A) Subscriber to outgoing trunk objective 0.01 or less;
(B) Incoming trunk to subscriber objective 0.02 or less; and
(C) Local trunk tandem objective 0.01 or less.
(vi) Groups of common service circuits are to be engineered
utilizing the full availability traffic tables that appear in paragraph
(p)(1)(i) of this section at the following stipulated probabilities:
(A) Outgoing trunks to 2/6 MF or dial pulse senders at B.001;
(B) Incoming trunks to 2/6 MF receivers at B.001;
(C) Incoming nondelay dial trunks to receivers at B.001; and
(D) Incoming trunks with start dial at B.01.
(vii) Remote Switching Terminals (RST's) shall meet the same grade
of service objectives as the host.
(3) Holding times. For the purpose of estimating the quantity of
common control circuits, the following average holding times may be
used. These holding times are conservative and represent the average
effective and ineffective call. If these holding times are to be used,
it must be so stated in appendix A of this section.
(i) The following average call holding times (HT) may be used.
------------------------------------------------------------------------
Type of Call HT--Seconds
------------------------------------------------------------------------
Intraoffice 120
EAS 150
Special Service, Intercept, Verification 60
Toll, CLR 300
Toll, S-S 24
Toll, PPCS 270
------------------------------------------------------------------------
(ii) The following average subscriber dialing holding times may be
used (times used to dial digits do not include machine time).
------------------------------------------------------------------------
Digits DP Pushbutton
Dialed Sec. Sec.
------------------------------------------------------------------------
Operator, Non-Pay Station 1 4.7 3.4
Special Service 3 7.7 5.0
Local 7 13.7 8.2
EAS 7 13.7 8.2
DDD: 1/0+7 8 15.2 9.0
DDD: 1/0+10 11 19.7 11.4
Dialing Time Per Digit - 1.5 0.8
Dial Tone Response - 3.2 2.6
------------------------------------------------------------------------
(iii) The following average incoming register holding times may be
used (times for digit registrations do not include machine time).
------------------------------------------------------------------------
Basic
-----------------
Additional
Holding Per Digit
Time Digits
(Sec.)
------------------------------------------------------------------------
MF Receiver from:
No. 5 Crossbar--Non-LAMA................. 1.4 4 0.14
[[Page 616]]
No. 5 Crossbar--LAMA..................... 2.3 4 0.14
Crossbar Tandem & 4A Toll................ 3.1 4 0.14
No. 1 ESS................................ 1.4 4 0.14
Key Pulsing Switchboard 5.2 4 0.60
DP Receivers--10 PPS from:
SxS...................................... 6.0 4 1.5
Dialing Switchboard...................... 6.6 4 1.3
4A Toll.................................. 5.6 5\1\ -
Crossbar Tandem.......................... 4.9 4 1.2
------------------------------------------------------------------------
\1\No reduction for fewer digits.
(iv) The following average sender holding times may be used (does
not include machine setup and release time).
------------------------------------------------------------------------
Basic
-----------------
Additional
Holding Per Digit
Time Digits
(Sec.)
------------------------------------------------------------------------
MF Senders:
No. 5 Crossbar........................... 1.5 4 0.14
Crossbar Tandem & 4A Toll\1\............. 2.0 4 0.14
TSP/TSPS................................. 2.4 7 0.14
SxS--CAMA, Called Number................. 3.7 7 0.14
SxS--CAMA, Calling Number................ 1.3 7 -
DP Senders--10 PPS:
With Overlap Pulsing\2\.................. 9.1 Up to 1.8
6
Without Overlap Pulsing.................. 4.6 4 1.2
------------------------------------------------------------------------
\1\Add 1.3 seconds for ANI outpulsing on special toll (0+) calls and on
DDD calls if AMA is not provided.
\2\Assumes overlap outpulsing starting on receiving of third digit;
applies only to calls handled on direct trunk groups.
(4) Traffic data requirements. (i) Traffic measurements are composed
of primarily two types--counts and usage. The following types of traffic
data recording are required:
(A) Peg count registers shall be incremented when a successful
network connection is established to a particular circuit group such as
trunks, senders, digital receivers, etc.
(B) Overflow count registers shall be incremented when access to a
particular circuit group is denied due to all resource busy condition.
(C) Network blockage count registers shall be incremented due to an
unavailability of a path in an access or switching matrix network.
(D) Usage measurements of the length of time associated with a
particular setup event or network connection shall be made. Usage data
measurements are normally collected by scanning circuit groups resources
every 10 or 100 seconds to determine busy/idle states. Measurements are
accumulated and read directly in CCS (hundred call seconds).
(E) Service delay measurements shall provide percentage counts of
the calls for a particular service that are delayed beyond a specified
interval of time, e.g., calls not receiving dial tone within 3 seconds
after call origination.
(ii) Traffic data shall be stored in electronic storage registers or
block of memory consisting of one or more traffic counters for each item
to be measured. The registers listed in paragraph (p)(4)(i) of this
section shall be associated with the interoffice trunks, switching
network and central control equipment in such a manner that the register
readings can be used to determine the traffic load and flow to, from and
within the system. Two-way trunks shall be metered to indicate inward
and outward seizures. The bidder shall indicate what registers are to be
supplied and their purpose.
(iii) The measured data shall be shown on a printout. It should be
possible to have local or remote printout, or both. Arrangement shall be
made for automatic data printout on command for 15-, 30-, or 60-minute
intervals as required, and be arranged for automatic start-stop and in
accordance with revenue separation procedures current at the time of
contract.
(iv) All traffic records shall have dates and times and office
identification.
(q) Transmission--(1) General. The transmission characteristics will
be governed by the fact that the switching matrix will be based on
digital operation. Unless otherwise stated, the requirements are in
terms of analog measurements made from Main Distributing Frame (MDF) to
MDF terminals, excluding cabling loss.
(2) Impedance. For the purpose of this section, the nominal input
impedance of analog ports in an end office shall be 900 ohms for 2-wire
ports and 600 ohms for 4-wire ports. Where the connecting facility or
equipment is other than this impedance, suitable impedance matching
shall be provided by the bidder when specified by the owner.
(3) Insertion loss. The insertion loss in both directions of
transmission at 1004
[[Page 617]]
Hz shall meet the following requirements when measured with a 0 dBm
input signal at 900 ohms (or 600 ohms, when required) at a temperature
of 77 deg.F 9 deg.F (25 deg.C 5 deg.C).
(i) Trunk-to-trunk or trunk-to-line. The loss shall be set between 0
and 0.5 dB for 2-wire to 2-wire, 2-wire to 4-wire, or 4-wire to 4-wire
voice frequency connections.
(ii) Line-to-line. The loss shall be set between 0 and 2 dB.
(iii) Direct digital interface. On a direct digital interface, the
loss through the office shall be adjusted to the proper level in the
receive side.
(iv) Stability. The long-term allowable variation in loss through
the office shall be 0.5 dB from the loss specified by the
bidder.
(4) Frequency response (loss relative to 1004 hz) shall meet the
following requirements.
(i) Trunk-to-trunk.
------------------------------------------------------------------------
Loss at 0 dBm0 Input\1\
------------------------------------------------------------------------
Frequency (Hz) 2-Wire to 2-Wire 4-Wire to 4-Wire
------------------------------------------------------------------------
60 20 dB Min.\2\ 16 dB Min.\2\
200 0 to 5 dB 0 to 3 dB
300-3000 -0.5 dB to 1 dB -0.3 to +0.3 dB
3300 1.5 dB Max. 1.5 dB Max.
3400 0 to 3 dB 0 to 3 dB
------------------------------------------------------------------------
\1\(-) means less loss and (+) means more loss.
\2\Transmit End
(ii) Line-to-line.
------------------------------------------------------------------------
Frequency (Hz) Loss at 0 dBm0 Input\1\
------------------------------------------------------------------------
60 20 dB Min.\2\
300 -1 to +3 dB
600-2400 1 dB
3200 -1 to +3 dB
------------------------------------------------------------------------
\1\(-) means less loss and (+) means more loss.
\2\Transmit End
(iii) Trunk-to-line. The trunk-to-line frequency response
requirements shall be a compromise between those values specified in
paragraphs (q)(4)(i) and (q)(4)(ii) of this section.
(5) Overload level. The overload level at 900 ohm impedance shall be
+3 dBm0.
(6) Gain tracking (linearity) shall meet the following requirements.
------------------------------------------------------------------------
Input Signal Level\1\ Maximum Gain Deviation
------------------------------------------------------------------------
+3 to -37 dBm0 0.5 dB
-37 to -50 dBm0 1 dB
------------------------------------------------------------------------
\1\1004 Hz reference at 0 dBm0.
(7) Return loss. (i) The specified return loss values are determined
by the service and type of port at the measuring (near) end. Two-wire
ports are measured (near end) at 900 ohms in series with 2.16
microfarads and 4-wire ports are measured at 600 ohms resistive.
(ii) Far end test terminations shall be as follows:
(A) Loaded line circuit--1650 ohms in parallel with the series
combination of .005 microfarads and 100 ohms;
(B) Nonloaded line circuit--800 ohms in parallel with the series
combination of .05 microfarads and 100 ohms;
(C) Special service line circuit including electronic lines and
carrier lines--900 ohms in series with 2.16 microfarads;
(D) Two-wire trunk--900 ohms in series with 2.16 microfarads; and
(E) Four-wire trunk--600 ohms.
(iii) For trunk-to-trunk (2-wire or 4-wire) connections the echo
return loss (ERL) shall be 27 dB, minimum and the singing return loss
(SRL) shall be 20 dB, minimum low and 23 dB, minimum high.
(iv) For trunk-to-line (2-wire or 4-wire) connections the ERL shall
be 24 dB, minimum and the SRL shall be 17 dB, minimum low and 20 dB,
minimum high.
(v) For line-to-line or line-to-trunk (2-wire or 4-wire) connections
the ERL shall be 18 dB, minimum and the SRL shall be 12 dB, minimum low
and 15 dB, minimum high.
(8) Longitudinal balance. The minimum longitudinal balance, with dc
loop currents of 20 to 70 mA, shall be 60 dB at all frequencies between
60 and 2000 Hz, 55 dB at 2700 Hz and 50 dB at 3400 Hz. The method of
measurement shall be as specified in the IEEE Std 455-1985, IEEE
Standard Test Procedure for Measuring Longitudinal Balance of Telephone
Equipment Operating in the Voice Band. Source voltage level shall be 10
volts root-mean-square (rms).
(9) 60 hz longitudinal current immunity. Under test conditions with
60 Hz, the system noise shall be no greater than 23 dBrnC0 as measured
using the configuration in Figure 1.
[[Page 618]]
Figure 1--Measuring the Effects of Low Frequency Induction
[GRAPHIC] [TIFF OMITTED] TC14NO91.091
Notes:
1. 900 ohm termination, C-message weighting, hold coil off
2. SNC Noise Choke 35 W, or equivalent
3. Test at 0.020 Adc and 0.070 Adc
4. 2 0.001 microfarad, 150 Vdc
(10) Steady noise (idle channel at 900 ohms impedance) measured on a
terminated call shall be 23 dBrnC0 maximum and average 18 dBrnC0 or
less. The 3K Hz Flat noise should be less than 35 dBrnC0 as an
objective.
(11) Impulse noise. The central office switching equipment shall be
capable of meeting an impulse noise limit of not more than five counts
exceeding 54 dBrnC0 voice band weighted in a 5-minute period on six such
measurements made during the busy hour. A Northeast Electronics Company
TTS 4002 Impulse Noise Counter, Wilcom T194C, Hewlett Packard 4945, or
equivalent, should be used for the measurements. The measurement shall
be made by establishing a normal connection from the noise counter
through the switching equipment in its off-hook condition to a quiet
termination of 900 ohms impedance. Office battery and signaling circuit
wiring shall be suitably segregated from voice and carrier circuit
wiring, and frame talking battery filters provided, if and as required,
in order to meet these impulse noise limits.
(12) Crosstalk coupling. Worst case equal level crosstalk is to be
75 dB minimum in the range 200-3400 Hz. This is to be measured between
any two paths through the system connecting a 0 dBm0 level tone to the
disturbing pair.
(13) Quantizing distortion. (i) The switching system shall meet the
following requirements.
------------------------------------------------------------------------
Minimum Signal to
Input Level (dBm0) 1004 or 1020 Hz Distortion with C-Message
Weighting
------------------------------------------------------------------------
0 to -30 33 dB
-30 to -40 27 dB
-40 to -45 22 dB
------------------------------------------------------------------------
(ii) Due to the possible loss of the least significant bit on direct
digital
[[Page 619]]
connections, a signal to distortion degradation of up to 2 dB may be
allowed where adequately justified by the bidder.
(14) Absolute delay. The absolute one-way delay through the
switching system, excluding delays associated with RST switching, shall
not exceed 1000 microseconds analog-to-analog measured at 1800 Hz.
(15) Envelope delay distortion. On any properly established
connection, the envelope delay distortion shall not exceed the following
limits.
------------------------------------------------------------------------
Frequency Range (Hz) Microseconds
------------------------------------------------------------------------
1000 to 2600 190
800 to 2800 350
600 to 3000 500
400 to 3200 700
------------------------------------------------------------------------
(16) Digital error rate. The digital switching system shall not
introduce an error into digital connections which is worse than one
error in 108 bits averaged over a 5-minute period.
(17) Battery noise. Noise across battery at power board distribution
bus terminals shall not exceed 35 dBrnC during the busy hour.
(18) Radio and television interference. The central office switching
equipment shall be designed and installed so that radiation of high
frequency noise will be limited so as not to interfere with radio and
television receivers.
(r) Timing intervals--(1) Type of equipment required. The equipment
for providing the specified timing intervals shall be solid-state.
(2) Tolerance. Where a range of time is specified as minimum and
maximum, the lower limits shall be considered as controlling and the
variation between this minimum and the actual maximum shall be kept as
small as practicable. In no case shall the quoted upper limit be
exceeded.
(3) Permanent signal timing. Lockout shall occur after an interval
of 20 to 30 seconds after receipt of dial tone if a ``permanent''
condition occurs prior to the transmission of dial pulses or pushbutton
dialing signals. This interval may be reduced appreciably during periods
of heavy traffic.
(4) Partial dial timing. Partial dial timing shall be within 15 to
37 seconds. This timing may be reduced appreciably during periods of
heavy traffic.
(5) Charge delay timing. Charge delay timing shall be within 2
seconds.
(6) Called party disconnect timing. Timed disconnect of a
terminating path under control of the called party shall be 10 to 32
seconds.
(7) Timing intervals for signals involved in distance dialing.
Timing intervals shall be provided to meet the requirements for distance
dialing equipment, which have been established in Bellcore document SR-
TSV-002275, BOC Notes on the LEC Networks--1990. Some of the more
important times which this document specifies are for:
(i) Disconnect signal;
(ii) Wink signal;
(iii) Start dialing signal;
(iv) Pulse delay signal;
(v) Go signal;
(vi) Digit timing; and
(vii) Sender, register, and link attachment timing.
(s) Power requirements and equipment--(1) Operating voltage. The
nominal operating voltage of the central office shall be 48 volts dc,
provided by a battery with the positive side tied to system ground.
(2) Batteries. (i) When battery cells of the lead antimony type are
specified, the pasted plate type shall be considered adequate.
(ii) When lead calcium cells are specified, no cell shall differ
from the average voltage of the string of fully charged cells by more
than 0.03 volt when measured at a charging rate in amperes
equivalent to 10 percent of the ampere hour capacity of the cells.
Similarly, when cells are fully charged and floating between 2.30 and
2.33 volts per cell, the cell voltage of any cell in a given string
shall not differ more than 0.03 volt from the average. These
requirements are for test purposes only and do not apply to operating
conditions.
(iii) Voltage readings shall be corrected by a temperature
coefficient of 0.0033 volt per degree F (0.006 per degree C), whenever
temperature variations exist between cells in a given string. This
correction factor shall also be applied when comparing cell voltages
taken at different times and at different temperatures. The correction
[[Page 620]]
factor shall be added to the measured voltage when the temperature is
above 77 deg.F (25 deg.C) and subtracted when the temperature is below
77 deg.F (25 deg.C).
(iv) The specific gravity readings of lead antimony cells at full
charge shall be 1.210 .010 at 77 deg.F (25 deg.C) at
maximum electrolyte height.
(v) When counter cells are supplied by the bidder, they shall be the
dry counter electromotive force (CEMF) type.
(vi) When lead antimony batteries are specified, they shall be
designed to last a minimum of 10 years when maintained on a full float
operation between 2.15 and 2.17 volts per cell. When lead calcium
batteries are specified, they shall be designed to last a minimum of 20
years when maintained on full float operation between 2.17 and 2.25
volts per cell. The battery shall be clearly designated as ``antimony''
or ``calcium'' by means of stencils, decals or other devices.
(vii) Each battery cell shall be equipped with an explosion control
device.
(viii) The battery size shall be calculated in accordance with
standard procedures. The battery in no case shall have a reserve
capacity in ampere hours less than four times the current capacity of
the largest charger.
(3) Charging equipment. (i) Charging shall be on a full float basis.
The rectifiers shall be of the full wave, self-regulating, constant
voltage, solid-state type and shall be capable of being turned on and
off manually.
(ii) When charging batteries, the voltage at the battery terminals
shall be adjustable and shall be set at the value recommended for the
particular battery being charged, providing it is not above the maximum
operating voltage of the switching system equipment. The voltage shall
not vary more than plus or minus 0.02 volt per cell between 10 percent
load and 100 percent load. Between 3 percent and 10 percent load, the
output voltage shall not vary more than plus or minus 0.04 volt per
cell. Beyond full load current, the output voltage shall drop sharply.
The output voltage shall be maintained with the line voltage variations
of plus or minus 10 percent. Provision shall be made to change the
output voltage of the rectifier manually to 2.25 volts per cell to
provide an equalization charge on the battery.
(iii) The charger noise shall not exceed 22 dBrnC when measured with
a suitable noise measuring set and under the rated battery capacitance
and load conditions as determined in Figure 2.
[[Page 621]]
Figure 2--Charger Noise Test
[GRAPHIC] [TIFF OMITTED] TR01JA93.386
The manufacturer may elect to eliminate the capacitor C from the
measurement.
A. Capacitance in [mu] F = 30,000 [mu] F per ampere-hour per cell.
For example, 25 cells at 100 ampere-hour would be equivalent to a
capacitance of:
(30,000 x 100)/25 = 120,000 [mu] F
B. The value of the resistive load R is determined by the nominal
battery voltage in volts divided by the full load rating in amperes. For
example, for a 48 volt battery and a full load current of 24 amperes,
the load resistance R is 48/24 = 2 ohms of appropriate power handling
capacity.
(iv) The charging equipment shall indicate a failure of charging
current, whether due to ac power failure, an internal failure in the
charger, or to other circumstances which might cause the output voltage
of the charger to drop below the battery voltage. Where a supplementary
constant current charger is used, an alarm shall be provided to indicate
a failure of the charger.
(v) Audible noise developed by the charging equipment shall be kept
to a minimum. Acoustic noise resulting from operation of the rectifier
shall be expressed in terms of dB indicated on a sound level meter
conforming to ANSI S1.4-1983, Specification for Sound Level Meters, and
shall not exceed 65 dB (A-weighting) measured at any point 5 feet (152.4
cm) from any vertical surface of the rectifier.
(vi) The charging equipment shall be designed so that neither the
charger nor the central office switching equipment is subject to damage
in case the battery circuit is opened for any value of load within the
normal limits.
(vii) The charging equipment shall have a capacity to meet the
requirements of central office size and special requirements of the
owner in appendix A of this section.
(viii) Minimum equipment requirement for chargers is one of the
following:
(A) Two chargers either capable of carrying the full office load as
specified in Item 12 of appendix A of this section; or
(B) Three chargers each capable of carrying half the office load as
specified in Item 12 of appendix A of this section.
(4) Miscellaneous voltage supplies. (i) Any power supply required
for voltages other than the primary battery voltage shall be provided by
either a solid-state dc-to-dc converter or dc-to-ac inverter,
[[Page 622]]
operating from the central office battery or from a separate battery and
charger. These power supplies shall meet the noise limit specified for
chargers in paragraph (s)(3)(iii) of this section, except the capacitor
``C'' shall be eliminated and the resistive load ``R'' shall be
determined by the nominal output voltage in volts divided by the full
load current rating in amperes. This requirement does not preclude the
use of commercial ac power to operate input/output devices.
(ii) Power converters required for the purpose of providing various
operating voltages to printed circuit boards or similar equipment
employing electronic components shall be provided in duplicate with each
unit capable of immediately assuming the full operating load upon
failure of a unit. An exception to the duplicate power converter
requirement permits nonduplicated power converter(s) to be utilized
where there is full compliance with the following criteria.
(A) The failure of any single nonduplicated power converter shall
not reduce the grade of service of common control and service circuits
to any individual line or trunk by more than 50 percent.
(B) The failure of any single nonduplicated power converter shall
not reduce the traffic carrying capacity of any interoffice trunk group
by more than 50 percent.
(C) In central office switching systems of 400 or more equipped
lines, any single nonduplicated power converter failure shall not cause
a complete loss of service to more than 100 equipped lines.
(D) In central office switching systems of less than 400 equipped
lines, any single nonduplicated power converter failure shall not cause
a complete loss of service to more than 25 percent of the total equipped
lines.
(5) Ringing generators. Ringing generators supplied on an ancillary
basis shall be selected from RUS Bulletin 1755I-100, List of Materials
Acceptable for Use on Telephone Systems of RUS Borrowers. Regardless of
whether the ringing is generated on an ancillary basis or is generated
integrally to the switching system, the ringing equipment shall meet the
requirements of this section.
(i) Ringing equipment provisioning. (A) Redundant ringing equipment
shall be provided. There shall be automatic transfer to the redundant
equipment within the period of one ringing cycle, in case of failure of
the equipment in use (either regular or standby). Automatic transfer
shall not take place under any other conditions. Manual transfer in each
direction shall be provided.
(B) An exception to the redundant ringing equipment requirement
permits nonredundant ringing equipment to be utilized where there is
full compliance with the following service criteria.
(1) In a central office switching system of 400 or more equipped
lines, a single nonduplicated ringing source failure shall not cause the
complete loss of ringing capability to more than 100 lines.
(2) In a central office switching system of less than 400 equipped
lines, a single nonredundant ringing source failure shall not cause the
complete loss of ringing capability to more than 25 percent of the total
equipped lines.
(ii) Output voltage. (A) The ringing generators shall have an output
voltage which approximates a sine wave and, as a minimum, shall be
suitable for ringing straight-line ringers. Although not a requirement
for RUS listing, decimonic, synchromonic, or harmonic ringing may also
be specified in appendix A of this section.
(B) The ringing generator shall obtain its energy from the nominal
48-volt office battery.
(C) The output of each generator shall have three or more voltage
taps or a single tap with associated variable control. Taps or control
shall be easily accessible as installed in the field. Software control
of ringing generator outputs via I/O devices may be provided in lieu of
taps. The taps, or equivalent, shall be designated L, M, and H. The
variable control shall have a locking device to prevent accidental
readjustment. The outputs at the terminals of the generators with a
voltage input of 52.1 volts and rated full resistive load shall be as
follows for the ringing frequencies provided:
[[Page 623]]
------------------------------------------------------------------------
Output Volts rms
(Tolerance 3 Volts)
Frequency Range (Hz) -----------------------
L M H
------------------------------------------------------------------------
16 2/3 through 20............................... 90 105 120
21 through 30................................... 95 110 120
31 through 42................................... 100 115 130
43 through 54................................... 110 125 140
------------------------------------------------------------------------
(D) No voltages in excess of the values in column H of the table in
paragraph (s)(5)(ii)(C) of this section shall be provided at the output
taps. Additional intermediate and/or lower taps may be provided without
restriction.
(iii) Voltage regulation. (A) The output voltage for resistive,
capacitive power factor of 0.8, and inductive power factor of 0.5 loads
from no load to full rated output with 52.1 volts input battery shall
not vary more than 3 percent from the output voltage
measured at 1/2 rated output, 1.0 power factor with 52.1 volts dc input
applied.
(B) The output voltage for resistive, capacitive power factor of
0.8, and inductive power factor of 0.5 from no load to full rated output
with input battery variations between 48-56 volts dc shall not vary more
than 10 percent from the output voltage measured at 1/2
rated output and 1.0 power factor with 52.1 volts dc input applied.
(C) The output voltage for resistive, capacitive power factor of
0.8, and inductive power factor of 0.5 loads from no load to full rated
output and with input battery variations between 44-56 volts dc shall
not vary more than +10/-15 percent from the output voltage measured at
1/2 rated output and 1.0 power factor with 52.1 volts dc input applied.
(iv) Cross ringing. Unwanted voltage caused by harmonic distortion
or intermodulation distortion shall not exceed 15 volts rms when
measured within 5 Hz of any other assigned ringing frequency
under any condition of load or input battery specified by paragraph
(s)(5)(iii) of this section.
(v) Frequency stability. At ambient temperature of 70 deg.
5 deg.F (21 deg. 0.3 deg.C), for any
combination of capacitive power factor of 0.8, inductive power factor of
0.5, and resistive loads with variations in input battery ranging from
44 to 56 volts, the output frequency shall not vary more than
1/3 Hz or 1 percent, whichever is less
stringent. At temperatures between 15 deg.F (4 deg.C) to 130 deg.F
(54 deg.C), and for any combination of resistive load and variations in
input battery ranging from 44-56 volts, the output frequency shall not
vary more than 1/3 Hz or 1 percent, whichever is
less stringent.
(vi) Self-protection on overloads. The ringing generator equipment
shall be capable of withstanding a short circuit across any pair of
output terminals for a period of 5 minutes without fuse operation or
damage.
(6) Interrupter equipment. (i) The interrupter shall be an integral
part of the switching system and shall be controlled by any call
processor or equivalent.
(ii) The ringing cycle provided by the interrupter equipment shall
not exceed 6 seconds in length. The ringing period shall be 2 seconds.
(7) Power panels. (i) Battery and charger control switches, dc
voltmeters, dc ammeters, fuses and circuit breakers, supervisory and
timer circuits shall be provided as required. Voltmeters shall be
provided as specified by the owner.
(ii) Portable or panel mounted frequency meters shall be provided as
specified by the owner unless the system is equipped to measure actual
ringing generator voltage and frequency outputs internally. If the
system is equipped to make such measurements and print the results, the
bidder is not required to provide a frequency meter.
(iii) Power panels, cabinets and shelves, and associated wiring
shall be designed initially to handle the exchange when it reaches its
ultimate capacity as specified by the owner.
(iv) The power panel shall be of the ``dead front'' type.
(t) Main distributing frames. (1) The main distributing frame shall
provide terminals for terminating all incoming cable pairs. Arresters
shall be provided for all incoming cable pairs, or for a smaller number
of pairs if specified, provided an acceptable means of temporarily
grounding all terminated pairs which are not equipped with arresters is
furnished.
(2) The current carrying capacity of each arrester and its
associated mounting shall coordinate with a 22 gauge
[[Page 624]]
copper conductor without causing a self-sustaining fire or permanently
damaging other arrester positions. Where all cable pairs entering the
central office are 24 gauge or finer, the arresters and
mountings need only coordinate with 24 gauge cable conductors.
Item 13 of appendix A of this section designates the gauge of the cable
conductors serving the host office. Item 7 of appendix B of this section
designates the gauge of the cable conductors serving the RST(s).
(3) Central office protectors shall be mounted and arranged so that
outside cable pairs may be terminated on the left side of protectors
(when facing the vertical side of the MDF) or on the back surface of the
protectors. Means for easy identification of pairs shall be provided.
(4) Protectors shall have a ``dead front'' (either insulated or
grounded) whereby live metal parts are not readily accessible.
(5) Protectors shall be provided with an accessible terminal of each
incoming conductor which is suitable for the attachment of a temporary
test lead. They shall also be constructed so that auxiliary test
fixtures may be applied to open and test the subscriber's circuit in
either direction. Terminals shall be tinned or plated and shall be
suitable for wire wrapped, insulation displacement or connectorized
connections.
(6) If specified in appendix A of this section, each protector group
shall be furnished with a factory assembled tip cable for splicing to
the entrance cable; the tip cable to be 20 feet (610 cm) in length
unless otherwise specified. Factory assembled tip cable shall be
22 gauge and selected from RUS Bulletin 1755I-100, List of
Materials Acceptable for Use on Telephone Systems of RUS Borrowers. Tip
cable requirements are provided in RUS Bulletin 345-87, PE-87, RUS
Specification for Terminating (TIP) Cable. Cables having other kinds of
insulation and jackets which have equivalent resistance to fire and
which produce less smoke and toxic fumes may be used if specifically
approved by RUS.
(7) Protectors shall be mounted on vertical supports, with centers
not exceeding 9 inches (22.9 cm). The space between protector units
shall be adequate for terminating conductors.
(8) Cable supporting framework shall be provided between the cable
entrance and the MDF when overhead cable entrance is specified in Item
14.3.3 of appendix A of this section.
(9) The main distributing frame shall be equipped with a copper
ground bus bar having the conductivity of a 6 American Wire
Gauge (AWG) copper conductor or a greater conductivity, or may consist
of another metal if specifically approved, provided it has adequate
cross-sectional area to provide conductivity equivalent to, or better
than, bare copper. A guardrail or equivalent shall also be furnished.
(10) Other features not specified in paragraph (t) of this section
may be required at the option of the owner, if checked in Item 13.4 of
appendix A of this section.
(11) Main frame protector makes and types shall be selected only
from RUS Bulletin 1755I-100, List of Materials Acceptable for Use on
Telephone Systems of RUS Borrowers. Protectors shall be capable of easy
removal.
(u) Electrical protection--(1) Surge protection. (i) Adequate
electrical protection of central office switching equipment shall be
included in the design of the system. The characteristics and
application of protection devices shall be such that they enable the
central office switching equipment to withstand, without damage or
excessive protector maintenance, the dielectric stresses and currents
that are produced in line-to-ground and tip-to-ring circuits through the
equipment as a result of induced or conducted lightning or power system
fault-related surges. All wire terminals connected to outside plant wire
or cable pairs shall be protected from voltage and current surges.
(ii) Central office switching equipment shall pass laboratory tests,
simulating the hostile electrical environment, before being placed in
the field for the purpose of obtaining field experience. There are five
basic types of laboratory tests which shall be applied to exposed
terminals in an effort to determine if the equipment will survive.
Figure 3 summarizes these tests and the minimum acceptable levels of
protection for equipment to pass them.
[[Page 625]]
Figure 3--Summary of Electrical Requirements and Tests
----------------------------------------------------------------------------------------------------------------
No. of
Application Peak Voltage Surge Applications &
Test Criteria or Current Waveshape Max. Time Comments
Between
----------------------------------------------------------------------------------------------------------------
Current Surge Low Impedance 500A or 10x1000 [mu] 5 each Polarity
Paths Exposed Lesser s at 1 minute
to Surges Current (See intervals
Fig. 5)
60 Hz Current Carrying High or Low 10A rms or 11 Cycles of 3 each Polarity
Impedance Lesser 60 Hz at 1 minute
paths Exposed Current (See (0.183 intervals
to Surges Fig. 6) Sec.)
AC Power Service Surge Voltage AC Power 2500V or +3 1.2x50 [mu] 5 each Polarity AC arrester, if
Service [sigma] s at 1 minute used, must be
Connection clamping V intervals removed.
of arrester Communications
employed at line arresters,
10kV/[mu] s if used, remain
in place.
Voltage Surge High Impedance 1000V or +3 10x1000 [mu] Same All primary
Paths Exposed [sigma] dc s arresters, if
to Surges breakdown of used, must be
arrester removed.
employed
Arrester Response Delay Paths +3 [sigma] 100V/[mu] s Same Same
protected by breakdown of rise decay
arresters, arrester to 1/2 V.
such as gas employed at in tube's
tubes, with 100V/[mu] s delay time
breakdown of rise
dependent on
V. rate of
rise.
----------------------------------------------------------------------------------------------------------------
(iii) Two categories of surge tests. (A) Current surge tests
simulate the stress to which a relatively low impedance path may be
subjected before main frame protectors break down. Paths with a 100 Hz
impedance of 50 ohms or less shall be subjected to current surges,
employing a 10 x 1000 microseconds waveshape as defined in Figure 4. For
the purpose of determining this impedance, arresters which are mounted
within the equipment are to be considered zero impedance. The crest
current shall not exceed 500A; however, depending on the impedance of
the test specimen this value of current may be lower. The crest current
through the sample, multiplied by the sample's 100 Hz impedance, shall
not exceed 1000 volts (V). Where sample impedance is less than two ohms,
crest current shall be limited to 500A as shown in Figure 5.
[[Page 626]]
Figure 4--Explanation of Surge Waveshape
[GRAPHIC] [TIFF OMITTED] TC14NO91.087
Surge Waveshape is defined as follows:
Rise Time x Time to Decay to Half Crest Value
(For example, 10 x 1000 [mu] s)
Notes:
T1 = Time to determine the rate of rise. The rate of rise
is determined as the slope between 10% and 90% of peak voltage or
current.
T2 = Time to 50% of peak voltage (decay to half value).
[[Page 627]]
Figure 5--Explanation of Surge Waveshape
[GRAPHIC] [TIFF OMITTED] TC14NO91.088
VL = Not to exceed 1000V
VB = Charging Voltage
Z100 = Test Specimen Impedance to be measured at 100 Hz.
RP = Parallel Resistance (Waveshape)
RS = Series Resistance (Current Limiting)
------------------------------------------------------------------------
Z100 RS RP VB
------------------------------------------------------------------------
0 5 [infin] 2500
1 4 [infin] 2500
2 3 [infin] 2500
3 2 [infin] 1670
4 1 [infin] 1250
5 0 [infin] 1000
7.5 0 15 1000
10 0 10 1000
15 0 7.5 1000
20 0 6.7 1000
25 0 6.25 1000
30 0 6 1000
40 0 5.7 1000
50 0 5.5 1000
------------------------------------------------------------------------
(B) Sixty Hertz (60 Hz) current-carrying tests should be applied to
simulate an ac power fault which is conducted to the unit over the cable
pairs. The test should be limited to 10 amperes rms at 60 Hz for a
period of 11 cycles (0.1835 seconds) and should be applied
longitudinally from line to ground (see Figures 3 and 6 of this
section).
[[Page 628]]
Figure 6--60 Hz Current Surge Test
[GRAPHIC] [TIFF OMITTED] TC14NO91.089
V--700 Volts RMS (Approximately 1000V Peak).
Z60--Test specimen impedance to be measured at 60 Hz.
RS--Series Resistance (current limiting) in each side of
line. (Source impedance never less than 50 [ohm] longitudinal.)
------------------------------------------------------------------------
Z60 Hz RS
------------------------------------------------------------------------
0 140
10 120
20 100
50 100
Over 50 100
------------------------------------------------------------------------
(C) AC power service surge voltage tests should be applied to the
power input terminals of ac powered devices to simulate switching surges
or lightning-induced transients on the ac power system. The test shall
employ a 1.2 x 50 microseconds waveshape with a crest voltage of 2500V.
Communications line protectors may be left in place for this test.
Borrowers are urged to install commercially available surge protectors
at the ac service entrance as part of their COE building program.
(D) Voltage surge tests simulate the voltage stress to which a
relatively high impedance path may be subjected before primary
protectors break down and protect the circuit. To assure coordination
with the primary protection while reducing testing to the minimum,
voltage surge tests should be conducted at a 1000 volts with primary
arresters removed for devices protected by carbon blocks, or the +3
sigma dc breakdown of other primary arresters. Surge waveshape should be
10 x 1000 microseconds.
(E) Arrester response delay tests are designed to stress the
equipment in a manner similar to that caused by the delayed breakdown of
gap type arresters when subjected to rapidly rising voltages. Arresters
shall be removed for these tests, the peak surge voltage should be the
+3 sigma breakdown of the arrester in question on a voltage rising at
100V per microsecond and the time for the surge to decay to half voltage
shall equal at least the delay time of the tube, as explained in Figure
7.
[[Page 629]]
Figure 7--Explanation of Arrester Response Delay Time
[GRAPHIC] [TIFF OMITTED] TC14NO91.090
The delay time is that period of time when the potential across an
arrester exceeds its dc firing level.
(iv) Five applications of each polarity for the surge tests and
three for the 60 Hz Current Carrying Test are the minimum required. All
tests should be conducted with not more than 1 minute between
consecutive applications in each series of three or five to a specific
configuration so that heating effects will be cumulative. As not all
tests are required in every application, nonapplicable tests should be
omitted. Tests should be conducted in the following sequence.
(A) Current Impulse Test.
(B) Sixty Hertz (60 Hz) Current Carrying Test.
(C) AC Power Service Impulse Voltage Test.
(D) Voltage Impulse Test.
(E) Arrester Response Delay Test.
(v) Tests should be applied between each of the following terminal
combinations for all line operating conditions.
(A) Line tip to ring.
(B) Line ring to ground.
(C) Line tip to ground.
(D) Line tip to ring tied together to ground.
(2) Extraordinary surge protection. A central office or RST may be
located in an area where ground conditions prevent the reasonable
economic achievement of a low resistance to ground and/or there exists a
greater than average probability of surge damage. Such an unusually
hostile operating environment shall be recognized and taken into
consideration by the bidder in the engineering and specification of the
central office switching system and line protection. This subject of
operating environment, ground conditions, etc., should be discussed at
the time of technical presentation to assure the owner that adequate
system protection will be provided by the bidder.
(3) Dielectric strength. Arresters shall be removed for all
dielectric strength tests. The duration of all dielectric strength tests
shall be at least 1 second. The applied potential shall equal or exceed
the +3 sigma dc breakdown voltage of the arrester, provided by the
[[Page 630]]
COE manufacturer. Direct current potentials shall be applied between all
line terminals and equipment chassis and between these terminals and
grounded equipment housings in all instances where the circuitry is dc
open circuit from the chassis, or connected to the chassis through a
capacitor.
(4) Insulation resistance. Following the dielectric tests, the
insulation resistance of the installed electrical circuits between wires
and ground, with the normal equipment grounds removed, shall not be less
than 10 megohms at 500 volts dc at approximately room temperature (68
deg.F (20 deg.C)) and at a relative humidity of approximately 50
percent. The measurement shall be made after the meter stabilizes,
unless the requirement is met sooner. Arresters shall be removed for
these tests.
(5) Self-protection. (i) All components shall be of the self-
protecting type, capable of being continuously energized at rated
voltage without injurious results.
(ii) The unit equipment shall not be permanently damaged by
accidental short circuits of any duration across either the central
office side tip and ring or the line side tip and ring. A test is to be
made with the unit energized at the highest recommended voltages.
(6) Static discharge. Assemblies subject to damage by static
discharge shall be identified and special handling instructions shall be
supplied.
(v) Miscellaneous--(1) Office wire. All office wire shall be of soft
annealed tinned copper wire meeting the requirements of ASTM
Specification B 33-91, Standard Specification for Tinned Soft or
Annealed Copper Wire for Electrical Purposes, and of suitable cross-
section to provide safe current carrying capacity and mechanical
strength. The insulation of installed wire, connected to its equipment
and frames, shall be capable of withstanding the same insulation
resistance and dielectric strength requirements as given in paragraphs
(u)(3) and (u)(4) of this section at a temperature of 120 deg.F (49
deg.C) and a relative humidity of 90 percent.
(2) Wire wrapped terminals. These terminals are preferred and where
used shall be of a material suitable for wire wrapping. The connections
to them shall be made with a wire wrapping tool with the following
minimum number of successive nonoverlapping turns of bare tinned copper
wire in contact with each terminal.
(i) 6 Turns of 30 Gauge.
(ii) 6 Turns of 26 Gauge.
(iii) 6 Turns of 24 Gauge.
(iv) 5 Turns of 22 Gauge.
(3) Protection against corrosion. All metal parts of equipment
frames, distributing frames, cable supporting framework, and other
exposed metal parts shall be constructed of corrosion resistant
materials or materials plated or painted to render them adequately
corrosion resistant.
(4) Screws and bolts. Screw threads for all threaded securing
devices shall be of American National Standard form in accordance with
Federal Standard H28, Screw-Thread Standards for Federal Services,
unless exceptions are granted to the manufacturer of the switching
equipment. All bolts, nuts, screws, and washers shall be of nickel-
copper alloy, steel, brass or bronze.
(5) Temperature and humidity range. The supplier shall furnish the
operating temperature and humidity ranges of the equipment being
provided in order that adequate heating and cooling may be supplied (see
Items 5.2.1 and 5.2.2 of appendix C of this section).
(6) Stenciling. Equipment units and terminal jacks shall be
adequately designated and numbered. They shall be stenciled so that
identification of equipment units and leads for testing or traffic
analysis can be made without unnecessary reference to prints or
descriptive literature.
(7) Equipment frame design. For newly designed systems,
consideration should be given to the desirability of providing frames
which can be installed in rooms of normal ceiling height [up to 10 feet
(305 cm)]. Where feasible, frames and equipment units shall be designed
for ready portability and high salvage value.
(8) Quantity of equipment bays. Consistent with system arrangements
and ease of maintenance, space shall be provided on the floor plan for
an orderly layout of future equipment bays that will be required for
anticipated traffic when the office reaches its ultimate size. Readily
accessible terminals
[[Page 631]]
shall be provided for connection to interbay and frame cables to future
bays. All cables, interbay and intrabay (excluding power), if
technically feasible, shall be terminated at both ends by use of
connectors.
(w) Remote switching terminal (RST)--(1) General. The RST is a
remotely located digital switching terminal which is placed at a
subordinate wire center for subscriber lines and is a part of the host
central office from a switching standpoint, and has hardware
interchangeable with the host office, except for items that are
applicable only to RST control and associated peripheral equipment. This
does not preclude the use of existing in-service remote units on a new
or upgraded host central office of the latest series generic or release.
(2) Span line. The RST is to be connected to the host central office
via a means compatible with T1 type span lines using a DS-1 interface.
This connection will be for control supervision and subscriber
communication. The RUS equipment specification for a span line is PE-60.
(3) Switching. (i) The RST may have its switching functions
controlled either by the host central office stored program control
processors or by local subordinate processors which communicate with the
host office processors.
(ii) As long as the connecting span line is intact, the subscribers
served by the RST shall have all features, traffic capacity, and
services including busy verification, available to all other subscribers
in the system.
(iii) The RST shall have available an emergency call processing
option which permits calling among all subscribers and from subscribers
to emergency numbers within the RST if control link connections to the
host central office are severed or otherwise disabled. The RST shall be
capable of rerouting normally used emergency numbers, such as 911, to
predetermined line terminations in this emergency stand-alone operating
condition. This RST emergency call processing option shall be provided
only when specified by the owner in Item 6.1 of appendix B of this
section.
(4) Subscriber line test. (i) Means shall be available on an
optional basis to the maintenance personnel to make subscriber line
tests from a common location for all subscriber lines including the RST.
(ii) If tests in paragraph (w)(4)(i) of this section are not
requested by the owner for a particular installation, a subscriber loop
test set (see paragraph (o)(2)(iii)(A) of this section) shall be
supplied at the RST with a means to access all lines.
(5) Housing. When housed in a building supplied by the owner, a
complete floor plan including ceiling height, power outlets, cable
entrances, equipment entry and travel, type of construction, and other
pertinent dimensions shall be supplied with this section.
(6) Power--(i) Chargers. A single charger meeting the requirements
of paragraph (s)(3) of this section (with the exception of paragraph
(s)(3)(viii) of this section) is required. An additional charger capable
of carrying the full load or a combination of three chargers each
capable of carrying half the load shall be supplied if redundant
chargers are specified in appendix B of this section.
(ii) Ringing equipment provisioning. (A) Ringing sources shall be
supplied in duplicate.
(B) An exception to the duplicated ringing source requirement
permits nonduplicated ringing source(s) to be utilized where there is
full compliance with the following service criteria.
(1) In a remote switching terminal (RST) of 400 or more equipped
lines, a single nonduplicated ringing source failure shall not cause the
complete loss of ringing capability to more than 100 lines.
(2) In a remote switching terminal (RST) of less than 400 equipped
lines, a single nonredundant ringing source failure shall not cause the
complete loss of ringing capability to more than 25 percent of the total
equipped lines.
(iii) Power converter. (A) Power converters required for the purpose
of providing various operating voltages to printed circuit boards or
similar equipment employing electronic components shall be provided in
duplicate with each unit capable of immediately assuming the full
operating load upon failure of a unit.
[[Page 632]]
(B) An exception to the duplicate power converter requirement
permits nonduplicated power converter(s) to be utilized where there is
full compliance with the following criteria.
(1) The failure of any single nonduplicated power converter shall
not reduce the grade of service of common control and service circuits
to any individual line or trunk by more than 50 percent.
(2) The failure of any single nonduplicated power converter shall
not reduce the traffic carrying capacity of any trunk group or service
links to a host office by more than 50 percent.
(3) In a remote switching terminal (RST) of 400 or more equipped
lines, any single nonduplicated power converter failure shall not cause
a complete loss of service to more than 100 equipped lines.
(4) In a remote switching terminal (RST) of less than 400 equipped
lines, any single nonduplicated power converter failure shall not cause
a complete loss of service to more than 25 percent of the total equipped
lines.
(7) Alarm. Sufficient system alarm points shall be provided from the
RST to report conditions to the host alarm system.
(x) Responsibilities of the bidder--(1) Central office layout. (i)
The successful bidder shall furnish tentative floor plan layout drawings
showing the arrangement of the equipment and the dimensions of major
equipment units. These drawings shall include minimum door dimensions
and ceiling heights required for installation, maintenance and
ventilation. If requested by the owner, the floor plan shall be such
that the battery, charger, power board, main distributing frame and wire
chief's test equipment are isolated from the other equipment by a
partition.
(ii) The layout drawings shall also show provision for the ultimate
capacity of the central office as specified by the owner.
(iii) After approval by the owner of the tentative floor plan, and
within 10 calendar days after approval of the contract by the
Administrator, the owner shall furnish the bidder the necessary data on
the actual floor plan. Within 20 calendar days after receiving the
necessary building data, the bidder shall then supply floor plan
drawings showing exact locations of all equipment, both initial and
ultimate, including points where connection to commercial power are
required, with voltage and wattage indicated at each point. Within 20
calendar days after receiving the floor plan drawings from the bidder,
the owner shall approve these drawings or take the necessary steps to
have the drawings changed to meet his approval. The layout planning must
be so coordinated between the owner and the bidder as not to delay the
scheduled equipment installation date.
(2) Shipment of main distributing frame (MDF). The bidder shall ship
the MDF equipment, with all necessary instructions to permit its
installation by the owner, at the time requested by the owner in
writing, provided such time is not earlier than 90 days prior to the
date specified for the shipment of the rest of the central office
equipment. If the owner or the owner's agent installs the main
distributing frame, the owner shall assume the responsibility and the
expense of proper installation according to information furnished by the
bidder.
(3) Drawings and printed material. (i) The bidder shall supply
instructional material for each exchange involved at the time of
delivery of the equipment. It is not the intent of this section to
require system documentation necessary for the repair of individual
circuit boards. The bidder shall supply three complete sets of legible
drawings, each set to include all of the following drawings and
documentation:
(A) A floor plan showing exact dimensions and location of each
equipment frame or item to a convenient scale;
(B) A block schematic drawing showing the various equipment
components in the system, and their identifying circuit number (e.g.,
MDF, line circuits, memory, trunks, etc.);
(C) Drawings of major equipment items such as frames, with the
location of major component items of equipment shown;
(D) Individual functional drawings for electrical circuits in the
system;
[[Page 633]]
(E) A detailed description of the operation of each circuit down to
a circuit package level;
(F) Wiring diagrams indicating the specific method of wiring used on
each item of equipment and interconnection wiring between items of
equipment;
(G) Sufficient software documentation to maintain and service the
system, including drawings showing principal aspects of the software
architecture;
(H) Individual maintenance drawings covering each equipment item
that contains replaceable parts, appropriately identifying each part by
name and part number, or, complete ordering instructions for all
replaceable parts if individual item drawings are not provided; and
(I) Job drawings including all drawings that are individual to the
particular office involved, such as main frame, power panel, test board,
etc.
(ii) The following information shall also be furnished:
(A) Complete index of the required drawings;
(B) Explanation of electrical principles of operation of the overall
switching system;
(C) List of tests which can be performed with each piece of test
equipment furnished, and explanation of the method of performing each
test;
(D) Sample of each form recommended for use in keeping records of
tests;
(E) Criteria for analyzing results of tests and determining
appropriate corrective action;
(F) General notes on the methods of isolating equipment faults to
specific printed circuit cards in the equipment;
(G) List of typical troubles which might be encountered, together
with general indications as to the probable location of each trouble;
(H) Special office grounding requirements;
(I) A site specific central office ground system acceptance
checklist that is consistent with industry practice; and
(J) A site specific layout of the master ground bar (MGB) showing
assignment of P, A, N, and I equipment areas.
(4) Distributing frame wire. The bidder shall provide sufficient
tinned copper conductor distributing frame wire for the initial
installation. The insulation of this wire shall be such that it will not
support combustion. The insulation shall have good abrasion resistance
and cut-through properties, exhibit good solder heat resistance, and be
suitable for wire wrap connections or insulation displacement
connections.
(5) Technical assistance service. A technical assistance service
shall be made available to assist the owner and its maintenance
personnel on a 24-hour, 7 days a week basis. There is to be assistance
available for both hardware and software problems. The necessary
interface devices shall be supplied by the bidder.
(6) Spare parts. (i) The spare parts bid price shall be based upon
the required quantities of spares shown in Item 6.2 of appendix C of
this section, and shall be added to the base bid for comparison purposes
in awarding the bid. It is the supplier's responsibility to provide all
spares required by this section. If the supplier neglects to list
certain spare parts in Item 6.2 of appendix C of this section, but they
are necessary to comply with this section, they shall be provided by the
supplier at no additional cost to the owner.
(A) ``Units'' are defined as user replaceable components used in the
central office equipment. ``Spare Parts'' are direct replacements for
units. Spare parts are necessary for the maintenance and diagnostic
operations where the suspected faulty unit may be removed and a spare
part substituted in anticipation that the trouble will be cleared.
(B) Examples of units for which spare parts should be furnished are
printed circuit cards; circuit pack assemblies; fuses; and power
supplies.
(C) Spare parts are not required as part of this addendum for items
such as connectorized cables, nuts, bolts, and similar hardware; nor for
items which can be obtained from sources other than the bidder such as
battery cells, chargers, powerboards, magnetic tape transport
assemblies, disk drives, ringing machines, recorded announcement
machines, loop extenders and voice frequency repeaters, fire bars,
teletypewriters, and video monitors.
[[Page 634]]
(D) When 100 or more like units are used in the hosts and RST's to
be bid, the quantity of spares to be furnished is determined by
multiplying the total number of like units in the contract by .05 or
.03, as applicable, and rounding off to the next lowest integer. For
example, 119 Class 1 units require five spares; 120 require six.
(E) When alternates are required, the price of the spare parts for
the alternates shall be included with the price of the alternate.
(F) For equipment in which the line cards consist of a number of
plug-in ``daughter'' boards on a ``mother'' board, the line card is
defined as the ``daughter'' board unit. In a similar manner for those
designs which have line cards backed up by a ``control card,'' the
``control card'' is not, by definition, a line card.
(G) The quantities of spare parts determined in paragraph (x)(6)(vi)
of this section are a minimum quantity. The bidder may add quantities of
spare parts to bring the number of spare parts up to the bidder's list
of spare parts necessary for proper operation in the field.
(ii) A Class 1 unit does not have automatic transfer to a redundant
or standby pool of identical units, and provides any function for 24 or
more lines or trunks or for all trunks in a group. Nonredundant digital
trunk interfaces are included in this category.
(iii) A Class 2 unit has automatic transfer to a redundant or
standby pool of identical units, and provides any function for 24 or
more lines or trunks or for all trunks in a group. Redundant digital
trunk interfaces and units of a redundant stored program processor are
included in this category.
(iv) A Class 3 unit does not have automatic transfer to a redundant
or standby pool of identical units and provides any function for no more
than 23 lines or trunks or for less than all trunks in a group.
Nonredundant analog trunks are included in this category. Excluded from
this category are line cards, which are in Class 4.
(v) A Class 4 unit has automatic transfer to a redundant or standby
pool of identical units and provides any function for no more than 23
lines or trunks or for less than all trunks in a group. Also, any line
cards are in Class 4.
(vi) The spare parts for all of the hosts and the RST's included in
this contract shall be provided as follows:
------------------------------------------------------------------------
Quantity of Units used in the CO's & RST's To Be Bid Required Quantity
----------------------------------------------------- of Spares By Class
of Unit
Class --- -------------------
1 2 3 4
------------------------------------------------------------------------
1 through 9 1 1 0 0
10 through 24 2 2 1 0
25 through 49 3 2 2 0
50 through 99 4 3 2 0
100 or More 5% 3% 3% 0
------------------------------------------------------------------------
(vii) As a part of the response to the bid, the supplier shall
furnish a list of units used by class and a list of spare parts to be
furnished with this contract. This list shall be placed in Item 6.2 of
appendix C of this section for only one of the host specifications
included in the entire contract.
(7) Environmental requirements. The bidder shall specify the
environmental conditions necessary for safe storage and satisfactory
operation of the equipment being bid. If requested, the bidder shall
assist the owner in planning how to provide the necessary environment
for the equipment.
(8) Unit costs for cost separation purposes. The successful bidder
shall present a cost breakdown of the central office equipment on a
discrete element basis 90 days after installation completion. This shall
include the various frames, switching and transmission components, and
software.
(9) Single-point grounding system acceptance. Qualified
representatives of the central office system supplier and the owner are
to conduct a thorough joint acceptance audit of the grounding system
prior to the central office being placed into service. A grounding
system acceptance checklist provided by RUS, which is consistent with
standard industry practice, will be used in conducting this audit. All
required grounding system corrections are to be made prior to placing
the central office system into full service operation. The successful
completion of this grounding system audit will constitute an acceptance
on the part of both parties, the owner and the central office supplier
(refer to paragraph (y)(5) of this
[[Page 635]]
section, and appendix D of this section).
(y) Installation. The following responsibilities apply to the
central office equipment installation and Remote Switching Terminal
(RST) installations, unless otherwise noted.
(1) Responsibilities of owner. The owner shall:
(i) Allow the bidder and its employees free access to the premises
and facilities at all hours during the progress of the installation;
(ii) Take such action as necessary to ensure that the premises are
dry and free from dust and in such condition as not to be hazardous to
the installation personnel or the material to be installed (not required
for an RST installed in a self-contained environmentally controlled
cabinet);
(iii) Provide heat or air conditioning when required and general
illumination in rooms in which work is to be performed or materials
stored (not required for an RST installed in a self-contained
environmentally controlled cabinet);
(iv) Provide suitable openings in buildings to allow material to be
placed in position (not required for an RST installed in a self-
contained environmentally controlled cabinet);
(v) Provide the necessary conduit and commercial and dc-ac inverter
output power to the locations shown on the approved floor plan drawings;
provide 120 volts, 60 Hz commercial power equipped with a secondary
arrester and a reasonable number of outlets for test, maintenance and
installation equipment; provide suitable openings or channels and ducts
for cables and conductors, from floor to floor and from room to room;
provide an acceptable central office grounding system and at a ground
resistance level that is reasonable for office site conditions (not
required for an RST installed in a self-contained environmentally
controlled cabinet);
(vi) Provide the necessary wiring, central office grade ground and
commercial power service, with a secondary arrester, to the location of
an exterior RST installation based on the voltage and load requirements
furnished by the bidder;
(vii) Test at the owner's own expense all lines and trunks for
continuity, leakage and loop resistance and ensure that all lines and
trunks are suitable for operation with the central office equipment
specified;
(viii) Make alterations and repairs to buildings necessary for
proper installation of material, except to repair damage for which the
bidder or its employees are responsible;
(ix) Connect outside cable pairs on the distributing frame and run
all line and trunk jumpers (those connected to protectors);
(x) Furnish all trunk, line, and party assignment information to
permit the bidder to program the data base memory within a reasonable
time prior to final testing;
(xi) Release for the bidder's use such portions of the existing
plant as are necessary for the proper completion of such tests as
require coordination with existing facilities including facilities for
T1 span lines with properly installed repeaters between the central
office and the RST installations;
(xii) Make prompt inspections as it deems necessary when notified by
the bidder that the equipment, or any part of the equipment, is ready
for acceptance;
(xiii) Provide and install adequate fire protection apparatus,
including one or more fire extinguishers or fire extinguishing systems
of the gaseous type that has low toxicity and effect on equipment; and
(xiv) Provide necessary access ports for cable, if underfloor cable
is selected.
(2) Responsibilities of bidder. The bidder shall:
(i) Allow the owner and its representatives access to all parts of
the buildings at all times during the installation;
(ii) Obtain the owner's permission before cutting into or through
any part of the building structure such as girders, beams, concrete or
tile floors, partitions or ceilings (not applicable to the installation
of lag screws, expansion bolts, and similar devices used for fastening
equipment to floors, columns, walls and ceilings);
(iii) Be responsible for reporting to the owner any damage to the
building
[[Page 636]]
which may exist or may occur during its occupancy of the building,
repairing all damage to the building due to carelessness of the bidder's
workforce, and exercising reasonable care to avoid any damage to the
owner's property;
(iv) Consult with the owner before cutting into or through any part
of the building structure where the fireproofing or moisture proofing
may be impaired;
(v) Take necessary steps to ensure that all fire fighting apparatus
is accessible at all times and all flammable materials are kept in
suitable places outside the building;
(vi) Not use gasoline, benzene, alcohol, naphtha, carbon
tetrachloride or turpentine for cleaning any part of the equipment;
(vii) Install the equipment in accordance with the specifications
for the office;
(viii) Run all jumpers, except line and trunk jumpers (those
connected to protectors);
(ix) Establish and update all data base memories with subscriber and
trunk information as supplied by the owner until an agreed turnover
time;
(x) Give the owner notice of completion of the installation at least
1 week prior to completion;
(xi) Permit the owner or its representative to conduct tests and
inspections after installation has been completed in order that the
owner may be assured that the requirements for installation are met;
(xii) Allow access, before turnover, by the owner or its
representative, upon request, to the test equipment which is to be
turned over as a part of the office equipment, to permit the checking of
the circuit features which are being tested and to permit the checking
of the amount of connected equipment to which the test circuits have
access;
(xiii) Make final charger adjustments using the manufacturer's
recommended procedure;
(xiv) Notify the owner promptly of the completion of work of the
central office, or such portions as are ready for inspection;
(xv) Correct promptly all defects for which the bidder is
responsible;
(xvi) Provide the owner with one set of marked prints, or strapping
prints, showing which of the various options and figures are in use on
each switching system as specified in paragraph (x)(3)(i) of this
section;
(xvii) Place the battery in service in compliance with the
recommendations of the battery manufacturer; and
(xviii) Furnish the owner with a record of the cell voltages and
specific gravity readings made at the completion of the installation of
the switching system and before it is placed in commercial service.
(3) Installation requirements. (i) All work shall be done in a neat,
workmanlike manner. Equipment frames or cabinets shall be correctly
located, carefully aligned, anchored and firmly braced. Cables shall be
carefully laid with sufficient radius of curvature and protected at
corners and bends to ensure against damage from handling or vibration.
Exterior cabinet installations for RST's shall be made in a permanent,
eye-pleasing manner.
(ii) All multiple and associated wiring shall be continuous, free
from crosses, reverses and grounds and shall be correctly wired at all
points.
(iii) An inspection shall be made by the owner or its
representatives prior to performing operational and performance tests on
the equipment. However, this inspection shall be made after all
installing operations which might disturb apparatus adjustments have
been completed. The inspection shall be of such character and extent as
to disclose with reasonable certainty any unsatisfactory condition of
apparatus or equipment. During these inspections, or inspections for
apparatus adjustments, or soldering, or in testing of equipment, a
sufficiently detailed examination shall be made throughout the portion
of the equipment within which such condition is observed, or is likely
to occur, to disclose the full extent of its existence, where any of the
following conditions are observed:
(A) Apparatus or equipment units failing to compare in quantity and
code with that specified for the installation;
(B) Apparatus or equipment units damaged or incomplete;
(C) Apparatus or equipment affected by rust, corrosion or marred
finish; or
[[Page 637]]
(D) Other adverse conditions resulting from failure to meet
generally accepted standards of good workmanship.
(4) Operational test requirements. (i) Operational tests shall be
performed on all circuits and circuit components to ensure their proper
functioning in accordance with appropriate applicable documents supplied
by the bidder.
(ii) A sufficient quantity of overall tests shall be made to ensure
proper operation of all specified features.
(iii) A sufficient quantity of locally originating and incoming
calls shall be made to prove the switching system can accept and process
calls to completion.
(5) Grounding system audit. (i) A grounding system audit shall be
performed to ensure that a viable single-point grounding system is in
place prior to the time the switching system is placed into full service
operation. It is suggested that such an audit be conducted at the time
the switching system is ready for turnover to the owner.
(ii) This single-point grounding system audit is to be conducted by
authorized representatives of the supplier and owner, and with the RUS
general field representative participating at his discretion.
(iii) The single-point grounding system audit is to be conducted
using the checklist contained in appendix D of this section.
(iv) Appendix D of this section shall be the principal single-point
grounding system audit guideline document. A supplemental checklist may
be prepared and provided by the switching system supplier which
recognizes unique grounding requirements related to their particular
switching system. The scope of this supplier checklist is to be confined
to unique and specific switching system requirements only. Acceptable
supplier supplemental grounding checklist must have prior approval of
and be on file with the Central Office Equipment Branch of the
Telecommunications Standards Division of RUS.
(v) It is the responsibility of the central office supplier to
ensure that the grounding system evaluation criteria contained in the
combination of the appendix D checklist of this section and their
optional supplemental checklist adequately fulfill requirements for
warranty coverage.
(vi) All deficiencies in the single-point grounding system are to be
corrected prior to the switching system being placed into full service
operation. Exceptions are permitted only by mutual agreement of the
owner and supplier and with written approval of the RUS general field
representative.
(vii) The acceptance statement facesheet of the audit checklist in
appendix D of this section shall be signed by authorized representatives
of the supplier and owner to indicate mutual approval of the single-
point grounding system. Copies of all completed grounding system audit
documents are to be provided to the supplier, owner and appropriate RUS
telephone program regional offices.
(The information and recordkeeping requirements of this section have
been approved by the Office of Management and Budget (OMB) under the
control number 0572-0059)
Appendix A to Sec. 1755.522--Specification for Digital, Stored Program
Controlled Central Office Equipment Detailed Requirements (Host)
(Information To Be Supplied by Owner)
Telephone Company Name__________________________________________________
________________________________________________________________________
Location
________________________________________________________________________
Central Office Name (By Location)
Town____________________________________________________________________
County__________________________________________________________________
State___________________________________________________________________
-------- Attended
-------- Unattended
-------- Remotes
1. General
1.1 Notwithstanding the bidder's equipment lists, the equipment and
materials furnished by the bidder must meet the requirements of
paragraphs (a) through (x), Appendix A and Appendix B of Sec. 1755.522.
1.2 Paragraphs (a) through (x) of Sec. 1755.522 cover the minimum
general requirements for digital, stored program controlled central
office switching equipment.
1.3 Paragraph (y) of Sec. 1755.522 covers requirements for
installation, inspection, and testing when such service is included as
part of the contract.
[[Page 638]]
1.4 Appendices A and B of Sec. 1755.522 cover the technical data
for application engineering and detailed equipment requirements insofar
as they can be established by the owner. These appendices are to be
filled in by the owner.
1.5 Appendix C of Sec. 1755.522 covers detailed information on the
switching network equipment and the common control equipment, and
information as to system reliability and heavy traffic delays as
proposed by the bidder. This appendix is to be filled in by the bidder
and must be presented with the bid.
1.6 Appendix D of Sec. 1755.522 is the single-point grounding
system audit checklist.
2. Numbering Scheme
2.1 This office shall be arranged to serve the following area and
office code(s):
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
If more than one code is to be served, discrimination shall be
determined by the following:
Number Translation ----
Separate Trunk Groups ----
Both (Explain in Item 16, Appendix A) ----
2.2 This office shall be arranged to provide EAS service to the
following:
------------------------------------------------------------------------
Connecting office Code Connecting office Code
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
2.2.1 Seven digits shall be dialed for all local and EAS calls.
2.3 Additional dialing procedures to be provided include the
following:
------------------------------------------------------------------------
Feature Required
------------------------------------------------------------------------
Station Paid Toll (Including Coin):
Home Numbering Plan Area (HNPA):
``1'' + 7 Digits.................................. --------------
``1'' + 10 Digits................................. --------------
Other (Explain in Item 16, Appendix A)............ --------------
Foreign Numbering Plan Area (FNPA):
``1'' + 10 Digits................................. --------------
Other (Explain in Item 16, Appendix A)............ --------------
------------------------------------------------------------------------
10XXX Dialing to Interexchange Carriers:
------------------------------------------------------------------------
Name Access code
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
------------------------------------------------------------------------
Feature Required
------------------------------------------------------------------------
Person, Special (Including Coin):
HNPA--``0'' + 7 Digits....................................
-----------
``0'' + 10 Digits.........................................
-----------
FNPA ``0'' + 10 Digits....................................
-----------
Other (Explain in Item 16, Appendix A)....................
-----------
Directory Assistance:
HNPA Local--411...........................................
-----------
``1'' + 411...............................................
-----------
HNPA Toll ``1'' + 555-1212................................
-----------
FNPA Toll ``1'' + NPA + 555-1212..........................
-----------
IDDD:
Operator Serviced 01......................................
-----------
Station-Station 011.......................................
-----------
------------------------------------------------------------------------
------------------------------------------------------------------------
No. to be
Other service codes dialed
------------------------------------------------------------------------
Wire Chief.................................................
------------
Repair Service.............................................
------------
Business Office............................................
------------
Emergency Calls to 911 Lines...............................
------------
Emergency Calls to 911 Trunks..............................
------------
Time.......................................................
------------
Weather....................................................
------------
100 Test Line..............................................
------------
102 Test Line..............................................
------------
105 Test Line..............................................
------------
Other (Explain in Item 16, Appendix A).....................
------------
------------------------------------------------------------------------
2.4 Assistance calls are answered: (Check appropriate items)
2.4.1 At the operator office in ----------------
2.4.1.1 By means of the regular interoffice toll trunks --------
2.4.1.2 By means of the regular interoffice EAS trunks --------
2.4.1.3 By means of a separate special service trunk group --------
2.4.1.4 Locally --------
Explain:
[[Page 639]]
3. Office Clock
3.1 This office is to be slave clock synchronized with another
office:
-------- Yes -------- No
(Explain details in Appendix A, Item 16 if ``Yes''.)
3.2 This office is to be a master clock office to provide
synchronization timing for other offices:
-------- Yes -------- No
(Explain details in Appendix A, Item 16 if ``Yes''.)
4. Interoffice Trunking Diagram
4.1 A sketch showing relative location of exchanges, RST's, and
number of circuits shall be included, also the office and area codes of
the direct trunk points. The diagram should indicate whether toll or EAS
trunk groups are ``High Usage'' or ``Final.'' Alternate routes should be
included. Indicate whether the trunk termination is direct digital or
analog.
5. Translator Function Chart
--------------------------------------------------------------------------------------------------------------------------------------------------------
First route Alternate routes
-----------------------------------------------------------------------------
Translator Send Translator Send
Called point Subscriber dials action -------------------------- action -------------------------
------------- -------------
Deletes Prefixes Deletes Prefixes
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
6. Line Circuit Requirements (Includes all lines associated with
RST's.)
[[Page 640]]
6.1 Types of Lines
--------------------------------------------------------------------------------------------------------------------------------------------------------
No. of lines
---------------------------------------------------------- No. of EAS areas Total No. of lines
Local service only both local and EAS service required
--------------------------------------------------------------------------------------------------------------------------------------------------------
6.1.1 Individual--Flat Rate......... ------------ ------------ ------------ ------------
6.1.2 Individual--Message Rate...... ------------ ------------ ------------ ------------
6.1.3 Pay Station................... ------------ ------------ ------------ ------------
6.1.4 Telephone Company Official ------------ ------------ ------------ ------------
Lines.
6.1.5 Wire Chief.................... ------------ ------------ ------------ ------------
6.1.6 911 Emergency Service Bureau ------------ ------------ ------------ ------------
Lines.
6.1.7 Number Hunting PBX Groups:.... ------------ ------------ ------------ ------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Type No. of lines
No. of Direct in dial Restricted ---------------------------------------------------------------- No. of EAS Total No. of
lines in No. of groups * service at COE Local service Both local and areas lines required
group Ground start Loop start only EAS service
------ ------ ------ ------ ------ ------ ------ ------ ------ ------
------ ------ ------ ------ ------ ------ ------ ------ ------ ------
------ ------ ------ ------ ------ ------ ------ ------ ------ ------
------ ------ ------ ------ ------ ------ ------ ------ ------ ------
------ ------ ------ ------ ------ ------ ------ ------ ------ ------
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Furnish translation information under Item 5.
[[Page 641]]
6.1.8 WATS Lines (Give details in Appendix A, Item 16)
Number of Inward WATS Lines --------
Number of Outward WATS Lines --------
6.1.9 Special Lines Required -------- (Explain in Item 16, Appendix A)
6.1.10 Total Number of Lines Required
Host ------ (Incl. DDI Concentrator Lines)
RST 1 ------
RST 2 ------
RST 3 ------
Total ------
6.1.11 Total Director Numbers Required ------
(Including RST's) (see Item 7.1, Appendix A)
6.1.12 Pay Station
Type ------------
New ---- Reused ----
(Describe in Item 16, Appendix A)
6.1.13 Line Concentrator
6.1.13.1 Supplied by Owner (see Item 16, Appendix A, for details)
---- Yes ---- No
6.1.13.2 Supplied by Bidder (If ``Yes'', attach REA Form 397g,
Performance Specification for Line Concentrators)
---- Yes ---- No
6.2. Data on Lines Required Range Extension
6.2.1 Number of non-pay station lines having a loop resistance,
including the telephone set, as follows:
No. of lines
1901-3200 ohms............................. ------
3201-3600 ohms............................. ------
6.2.2 Number of pay station lines having loop resistance, excluding the
telephone set, greater than:
No. of lines
1200 ohms (For Prepay)..................... ------
1000 ohms (For Semi-Postpay Operation)..... ------
6.2.3 Range extension equipment is to be provided:
6.2.3.1 Loop Extenders: Total Quantity ------
By Bidder--Quantity ------
By Owner--Quantity ------
(Explain in Item 16, Appendix A)
6.2.3.2 VF Repeaters: Total Quantity ------
By Bidder--Quantity ------
(Bidder must have information on loading and cable size.)
By Owner--Quantity ------
(Explain in Item 16, Appendix A)
6.2.3.3 Range extension may be furnished as an extended range line
circuit at the option of the supplier. If this option is used,
the quantities of loop extenders and VF repeaters will be
different from the quantities listed above (see Item 6.1,a,
Appendix C).
---- Yes ---- No
7. Traffic Data-Line Originating and Terminating Traffic
7.1 Originating Line Traffic--Estimated per Busy Hour (Includes all
Lines Associated With RST's):
[[Page 642]]
--------------------------------------------------------------------------------------------------------------------------------------------------------
(a) CCS per Main Station (b) No. of Main Stations (axb) Total CCS No. of Lines Required \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ind.--Res....................... ---------- ---------- ---------- ----------
Ind.--Bus....................... ---------- ---------- ---------- ----------
Special Lines................... ---------- ---------- ---------- ----------
Pay Station..................... ---------- ---------- ---------- ----------
Telco Official.................. ---------- ---------- ---------- ----------
Wire Chief...................... ---------- ---------- ---------- ----------
No. Htg. or PBX................. ----------(\2\) ----------(\3\) ---------- ----------
WATS............................ ---------- ---------- ---------- ----------
Data Service.................... ---------- ---------- ---------- ----------
911 Emerg. Service.............. ---------- ---------- ---------- ----------
Total......................... ............................ ---------- ---------- ----------(\4\)
-----------------------------------------------------------------------------------------
............................ (c) (d) (e)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ See Appendix A, Item 6.1.
\2\ This figure is the CCS per PBX trunk.
\3\ This figure is the number of PBX trunks.
\4\ This is the total number of line equipments required. The number to be provided will be determined by the equipment design of the system of the
selected bidder. See Appendix C, Item 3.1.1.2.
[[Page 643]]
7.2 Average Originating CCS per Line per Busy Hour
(d)/(e)=----/ ----=---- CCS/Line
This office shall be engineered to handle an initial average
originating busy hour traffic of ---- CCS per line. It is anticipated
that the average originating busy hour traffic will increase to ---- CCS
per line.
Originating Traffic Attributed to Host Only ---- CCS/Line
7.3 Terminating Traffic--Estimated CCS per Busy Hour
It is assumed that the total CCS for terminating traffic is the same
as for originating traffic. Since digital switch networks are on a
terminal per line basis, the terminating CCS per line will be the same
as the originating CCS per line as shown in Item 7.2, Appendix A.
Terminating Traffic Attributed to Host Only ---- CCS/Line
7.4 Percent of Pushbutton Lines ----
7.5 Anticipated Ultimate Capacity (20 years)
7.5.1 Subscriber Lines
Host -------- (Incl. DDI Concentrator Lines)
RST 1 --------
RST 2 --------
RST 3 --------
Total --------
[[Page 644]]
8. Trunk Circuit Requirements
8.1 Interoffice Trunking
8.1.1 Trunking Requirements
----------------------------------------------------------------------------------------------------------------
1. Connecting Office................ ................. ................. ................. .................
2. Use of Trunk..................... ................. ................. ................. .................
3. Trk. Grp. Ntwk. Connection 1..... ................. ................. ................. .................
4. Quantity Equipped................ ................. ................. ................. .................
5. Ultimate % Growth................ ................. ................. ................. .................
6. CCS Capacity..................... ................. ................. ................. .................
7. Direction........................ ................. ................. ................. .................
8. No. Digits Dialed................ ................. ................. ................. .................
9. No. Digits Outpulsed............. ................. ................. ................. .................
10. No. Digits Inpulsed............. ................. ................. ................. .................
11. Type Signaling.................. ................. ................. ................. .................
12. Type Pulsing.................... ................. ................. ................. .................
13. Carrier Type (2-Wire)........... ................. ................. ................. .................
14. Carrier Type (4-Wire)........... ................. ................. ................. .................
15. Physical........................ ................. ................. ................. .................
16. Repeat Coils 2.................. ................. ................. ................. .................
17. DX Signaling Set................ ................. ................. ................. .................
18. Other Type Signaling............ ................. ................. ................. .................
19. Delay Dial...................... ................. ................. ................. .................
20. Direct Digital Interface........ ................. ................. ................. .................
21. a. Feature Group B.............. ................. ................. ................. .................
b. Feature Group C.............. ................. ................. ................. .................
c. Feature Group D.............. ................. ................. ................. .................
----------------------------------------------------------------------------------------------------------------
1 Designation of trunk group network connection involves the following categories:
IC--Direct Inter-LATA Connecting Trunk=(IC/POP)
TC--Tandem Connecting Trunks
IT--Intertandem Connecting Trunks
IL--Intra-LATA Connecting Trunks
TIC--Tandem Inter-LATA Connecting Trunks
Misc.--Intercept, Busy Verification, etc.
2 Omit repeating coils for carrier derived trunks.
[[Page 645]]
8.1.2 Pads for 4-Wire Carrier (7dB and 16dB)
Total Quantity ------
By Bidder Quantity ------
By Owner Quantity ------
Refer to the attached information regarding connecting company trunk
circuit drawing numbers and name of manufacturer.
8.2 Switched Traffic Data
8.2.1 Originating Traffic
--------------------------------------------------------------------------------------------------------------------------------------------------------
No. of digits Sender sig.
Type CCS H.T. secs. BHC out-pulsed mode Remarks
--------------------------------------------------------------------------------------------------------------------------------------------------------
Toll ``0''-\1\.......................................... .............. .............. .............. .............. .............. ..............
Toll ``0''+7 \1\ \2\.................................... .............. .............. .............. .............. .............. ..............
Toll ``0''+10 \1\ \2\................................... .............. .............. .............. .............. .............. ..............
Toll S-S ``1''+7 \2\.................................... .............. .............. .............. .............. .............. ..............
Toll S-S ``1''+10 \2\................................... .............. .............. .............. .............. .............. ..............
Toll Other.............................................. .............. .............. .............. .............. .............. ..............
Special Service......................................... .............. .............. .............. .............. .............. ..............
Intercept............................................... .............. .............. .............. .............. .............. ..............
Intraoffice............................................. .............. .............. .............. XXXXXXX XXXXXXX ..............
EAS..................................................... .............. .............. .............. .............. .............. ..............
EAS..................................................... .............. .............. .............. .............. .............. ..............
EAS..................................................... .............. .............. .............. .............. .............. ..............
Tandem.................................................. .............. .............. .............. .............. .............. ..............
Tandem.................................................. .............. .............. .............. .............. .............. ..............
Tandem.................................................. .............. .............. .............. .............. .............. ..............
911 Emerg. Service...................................... .............. .............. .............. .............. .............. ..............
-----------------------------------------------------------------------------------------------
Total............................................... .............. .............. .............. .............. .............. ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ PPCS traffic assumed to be divided 20 percent ``0''- and 80 percent ``0''+ if unknown.
\2\ Toll calls assumed to be divided two-thirds 7 digits and one-third 10 digits.
Busy Hour Attempts=BHC Total x 1.4=----
8.2.2 Terminating Traffic
----------------------------------------------------------------------------------------------------------------
No. of
Type CCS H.T. secs. BHC digits Receiver Remarks
inpulsed sig. mode
----------------------------------------------------------------------------------------------------------------
Toll Compl........................ ........... ........... ........... ........... ........... ...........
Test & Ver........................ ........... ........... ........... ........... ........... ...........
Intraoffice....................... ........... ........... ........... ........... ........... ...........
EAS............................... ........... ........... ........... ........... ........... ...........
EAS............................... ........... ........... ........... ........... ........... ...........
EAS............................... ........... ........... ........... ........... ........... ...........
Tandem............................ ........... ........... ........... ........... ........... ...........
Tandem............................ ........... ........... ........... ........... ........... ...........
Tandem............................ ........... ........... ........... ........... ........... ...........
-----------------------------------------------------------------------------
Total......................... ........... ........... ........... ........... ........... ...........
----------------------------------------------------------------------------------------------------------------
9. Checklist of Features Required
9.1 Alternate Routing........................................... .....
(Explain in Item 16, Appendix A)
9.2 Data Service................................................ .....
(Explain in Item 16, Appendix A)
9.3 This office shall be:
9.3.1 End Office Only........................................... .....
9.3.2 End Office and Intermediate Tandem........................ .....
(Explain in Item 16, Appendix A)
9.3.3 End Office and Access Tandem.............................. .....
(Explain in Item 16, Appendix A)
9.4 Billing Data
----------------------------------------------------------------------------------------------------------------
Send ANI Store billing data
feature group -------------------------
Trunk group --------------- Pollable
B C D AMA system system
----------------------------------------------------------------------------------------------------------------
9.4.1 This office only................................... ........... ... ... ... ........... ...........
9.4.2 Trunks from Tributaries............................ ........... ... ... ... ........... ...........
----------------------------------------------------------------------------------------------------------------
9.4.3 Local Message Detail Recording:
----------------------------------------------------------------------------------------------------------------
9.5 Pollable Systems
9.5.1 Polling device to be provided on this contract
[[Page 646]]
---- Required
---- Not Required
(Provide details in Item 16, Appendix A)
9.5.2 Pollable system to be backed up by tape or disc standby
---- Required
---- Not Required
9.6 AMA Format
9.6.1 Bellcore Format
---- Required
---- Not Required
(Provide details in Item 16, Appendix A)
10. Miscellaneous Operating Features
10.1 Busy Verification
10.1.1 By dedicated trunk from toll operator: ----
10.1.1.1 One-Way, Inward ----
10.1.1.2 Two-Way (Busy verification inward, intercept outward) ----
10.1.2 By prefix digit over intertoll trunk ----
(Indicate digit(s) dialed) ----
10.1.3 Access by Switchman
10.1.3.1 Dedicated Trunk ----
10.1.3.2 Multiple of Operator Trunk ----
10.2 Intercept Facilities
10.2.1 Vacant code, disconnected number, and unassigned number
intercept shall be: (Check One)
By recorded announcement:
Without cut-through to operator ----
With cut-through to operator ----
By operator ----
10.2.2 Changed number intercept shall be: (Check One)
By recorded announcement:
Without cut-through to operator ----
With cut-through to operator ----
By operator ----
By automatic intercept system (AIS) in distant office ----
10.2.3 Method of Reaching Operator, if required:
Separate trunk group ----
Regular interoffice toll trunks with idle trunk selecting over at
least three trunks when three or more toll trunks are equipped ----
10.2.4 Number of separate intercept trunk circuits ----
10.3 Line Load Control
10.3.1 Line load control facilities are:
---- Required ---- Not Required
(Explain in Item 16, Appendix A)
10.4 Service Observing Facilities
10.4.1 Service observing facilities are:
---- Required ---- Not Required
(Explain in Item 16, Appendix A)
10.5 Hotel-Motel Arrangements
10.5.1 Hotel-motel arrangements for operation of message registers at
the subscriber's premises are:
---- Required ---- Not Required
(Explain in Item 16, Appendix A)
10.5.1.1 How are message registers to be activated?
Line Reversal ----
Third Wire ----
Other ----
(Explain in Item 16, Appendix A)
10.6 Nailed-Up Connections
---- Required ---- Not Required
(Explain in Item 16, Appendix A)
10.7 Vertical Services: (RST Lines are Included)
Initially Ultimate
10.7.1 Call Waiting--No. of Lines.... ------------ ------------
10.7.2 Call Forwarding--No. of Lines. ------------ ------------
---- Local ---- Remote
(Explain in Item 16, Appendix
A).
10.7.3 Abbreviated Dialing No. of ------------ ------------
Lines.
No. of Codes per Line ---- for
---- Lines
No. of Codes per Line ---- for
---- Lines
10.7.4 Three-Way Calling--No. of ------------ ------------
Lines.
CCS Per Line.................. ------------ ------------
10.7.5 Other ----
(Explain in Item 16, Appendix A)
11. Maintenance Facility Requirements
11.1 Alarm Signals
11.1.1 Handled locally ----
Explain in Detail:______________________________________________________
________________________________________________________________________
________________________________________________________________________
11.1.2 Transmitted to attended point
11.1.2.1 Via operator office trunks ----
11.1.2.2 Via printout or other display service ----
Explain in Detail:______________________________________________________
________________________________________________________________________
________________________________________________________________________
11.1.2.3 Type of tone to operator
11.1.2.3.1 Distinctive tone (see (i)(2)(ix) of Sec. 1755.522) ----
11.1.2.3.2 Other
Explain in Detail:______________________________________________________
________________________________________________________________________
________________________________________________________________________
11.1.3 Alarm checking signals for carrier and mobile radio systems
11.1.3.1 Minor Alarm.............................................. ...
11.1.3.2 Major Alarm.............................................. ...
[[Page 647]]
11.1.3.3 Terminals for both....................................... ...
11.2 Trouble Location and Test
11.2.1 Outside plant and stations (check desired items)
11.2.1.1 Subscriber's loop test circuit:
11.2.1.1.1 As part of the maintenance center...................... ...
11.2.1.1.2 Separately............................................. ...
11.2.1.2 Remote test set (Explain in Item 16, Appendix A)......... ...
11.2.1.3 Dial speed test circuit (Explain in Item 16, Appendix A). ...
11.2.1.4 Pushbutton dialing test circuit.......................... ...
11.2.1.5 Howler (per (o)(2)(iii)(C) of Sec. 1755.522)............ ...
11.2.1.6 Hand test sets, number required ---- (Explain in Item 16,
Appendix A).......................................................
11.3 Transmission Tests
11.3.1 Furnish reference tone
Yes ----
No ----
------------------------------------------------------------------------
Time interval for
Frequencies and order in which applied application of each
frequency
------------------------------------------------------------------------
---- Hz................................... ---- Seconds
---- Hz................................... ---- Seconds
---- Hz................................... ---- Seconds
---- Hz................................... ---- Seconds
------------------------------------------------------------------------
11.3.2 Test Lines
11.3.2.1 Test Line 100 ----
11.3.2.2 Test Line 102 ----
11.3.2.3 Test Line 104 ----
11.3.2.4 Test Line 105 ----
(Explain in Item 16, Appendix A)
11.3.2.5 Test Line 107 ----
11.3.2.6 Remote Office Test Line ----
(Explain in Item 16, Appendix A)
11.4 Line Testing
11.4.1 Automatic line insulation testing
Yes ----
No ----
11.4.2 Owner supplied equipment
Yes ----
No ----
11.4.2.1 Vendor supplied interface only
Yes ----
No ----
If supplied by owner, explain in Item 16, Appendix A, including
manufacturer, model, location.
11.5 Remote Control
11.5.1 Remote control of the system shall be provided.
Yes ----
No ----
If required, explain in Item 16, Appendix A, including number, type
and location.
12. Power Equipment Requirements (Host Office Only)
12.1 Central Office Battery
12.1.1 A battery reserve of ---- busy hours shall be provided for
this office when it reaches ---- lines at the ultimate anticipated
traffic rates specified in Item 7.2, Appendix A.
12.1.1.1 The owner will furnish a standby generator, permanently
installed in this office, with capacity sufficient to power air
conditioning equipment required for cooling of the central office
equipment and to maintain an adequate dc supply in the event of a
failure of the commercial ac supply.
Yes ----
No ----
12.1.2 Type of battery: (Check One)
Lead Calcium ----
Lead Antimony ----
12.1.3 Voltmeter (portable 3-60-150 volt scale, 1% accuracy) shall
be furnished.
Yes ----
No ----
12.1.4 Hydrometer in a hydrometer holder with glass or plastic drop
cup shall be furnished.
Yes ----
No ----2112.1.5 Type of battery rack required: (Check One)
Two Tier ----
Other ----
Explain:
12.1.6 Special equipment power requirements (carrier, voice
frequency repeaters, etc.). Drain in amperes ----
12.1.6.1 Supply all necessary equipment to provide the following
48-volt battery taps:
------------------------------------------------------------------------
Fuse (or circuit breaker)
Number of circuits size
------------------------------------------------------------------------
............................
............................
............................
............................
------------------------------------------------------------------------
12.2 Charging Equipment
12.2.1 Charging equipment shall be provided capable of charging the
office battery on a full float basis when the office reaches ---- lines
at the ultimate anticipated traffic rates specified in Item 7.2,
Appendix A.
12.2.2 Charger input rating shall be:
[[Page 648]]
------------------------------------------------------------------------
3-Phase Connection:
------------------------------------------------------------------------
Voltage ---- 3-Wire ----
Phase ---- 4-Wire ----
Frequency ---- Delta ----
Y ----
------------------------------------------------------------------------
12.3 Ringing Equipment
12.3.1 Solid-state ringing equipment in accordance with paragraph
(s)(5)(i) of Sec. 1755.522 shall be provided for generating the
frequencies specified by check marks in the following table. Ringing
generator sets serving the entire office shall each be sized to carry
the full office ringing load when the office size reaches ---- lines at
the ultimate anticipated traffic rates specified in Item 7.2, Appendix
A.
12.3.2 Ringing frequencies to be supplied:
------------------------------------------------------------------------
Maximum
Frequency No. of
in Hz telephones
------------------------------------------------------------------------
Single Frequency............................ 20 ... ..........
Decimonic................................... 20 ... ..........
30 ... ..........
40 ... ..........
50 ... ..........
Harmonic.................................... 16\2/3\ ... ..........
25 ... ..........
33\1/3\ ... ..........
50 ... ..........
Synchromonic................................ 20 ... ..........
30 ... ..........
42 ... ..........
54 ... ..........
------------------------------------------------------------------------
12.3.3 Furnish frequency meter (accurate within 1.3 Hz) and
voltmeter (5% accuracy) for ringing measurements (see paragraph
(s)(7)(ii) of Sec. 1755.522). Check One:
Panel Mounted ----
Portable ----
Not Required ----
12.4 Power Board
The power panel and associated wiring shall be of ample size to meet
the load requirements when this office reaches ---- lines at the
ultimate anticipated traffic rates specified in Item 7.2, Appendix A.
13. Distributing Frame Requirements (Host Office Only)
13.1 Total number of outside plant cable pairs to be terminated... ...
13.1.1 Gauge of outside plant cable pairs......................... ...
13.2 Number of outside plant cable pairs to be protected.......... ...
13.3 Number of additional protector pair units to be provided on ...
MDF...............................................................
Explain:
13.4 Main Frame Details
Is present MDF to be reused?
Yes ----
No ----
If ``Yes,'' Type ----
Reused protectors are:
---- (Mfgr.)
---- (Type)
13.4.1 Number of pairs of arrester units (switching equipment) ----
13.4.2 Number of pairs of gas tube arrester units (special
equipment) ----
13.4.2.1 Gas tubes to be:
---- light,
---- medium,
---- heavy,
---- max. duty units
13.4.2.2 Fail shorted/low breakdown failure mode required
Yes ----
No ----
13.4.2.3 Breakdown voltage of gas tube arresters ----
13.4.3 Number of terminated pairs to be grounded ----
13.4.4 Factory assembled tip cable
Yes ----
No ----
13.4.4.1 Tip cable length [if other than 20 feet (610 cm)]
----
13.4.4.2 Tip cable formed
Up ----
Down ----
13.4.5 Pairs per vertical ----
13.4.6 Height of vertical ---- feet ---- inches
14. Building and Floor Plan Information (Host Office Only)
14.1 Equipment is to be installed in an existing building (Attach
detailed plan.) ----
14.2 A new building is planned ----
14.2.1 Tentative plan (Note to Engineer: Show sketch without
dimensions.)
14.3 Detailed Arrangements
14.3.1 Partition required (to isolate space containing battery,
charger, power board, test panel, main distributing frame and
subscriber's loop test circuit (wire chief's test desk) from that of the
remaining equipment).
Yes ----
No ----
14.3.2 Vestibule required
Yes ----
No ----
14.3.3 Cable entrance
Overhead----
Underground ----
14.3.4 Additional floor space will be required for the following
equipment which is being furnished by the owner or by the connecting
company:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
14.3.5 The office will be arranged for
Overhead Interbay Cabling ----
[[Page 649]]
Underfloor (Computer Room Type) Interbay Cabling ----
14.3.6 Is earthquake bracing required?
Yes ----
No ----
(If ``Yes,'' explain zone and criteria used for zone in Item 16,
Appendix A.)
14.3.7 Office ground will be ---- ohms or less (Refer to Item 4.6.3
of RUS TE&CM 810.)
14.3.8 The office is considered to be in the following category for
lightning damage probability based on the Figure 1 map of RUS TE&CM 823
(see paragraph (u)(2) of 1755.522).
---- Very High
---- Higher than Average
---- Average
---- Lower than Average
---- Very Low
14.3.9 The following is additional information regarding operating
environment conditions which should be considered in determining system
protection requirements (tower in vicinity, high exposure, etc.):
15. Alternate Requests
16. Explanatory Notes (Include a detailed description of any equipment
to be reused, or otherwise supplied by the owner, loop extenders,
subscriber carrier, VF repeaters, etc.)
Appendix B to 7 CFR 1755.522--Detailed Information on Remote Switching
Terminals (RST's)
(Complete One Form For Each RST)
1. Number of Subscriber Lines (These lines included in totals in Item 6,
Appendix A).
1.1 Single-Party: -------- Flat Rate -------- Message Rate.
1.2 Semi-Postpay Pay Station --------.
1.3 Prepay Pay Station --------.
1.4 PABX Lines -------- Loop Start-------- Ground Start --------
Restricted at Office -------- Other --------
(Describe in Item 12, Appendix B)
1.5 Number of lines to be pushbutton ----------------
1.6 911 Emergency Lines --------
1.7 Anticipated ultimate capacity (20-Year) --------
2. Traffic
2.1 Originating traffic per line--CCS/BH: -------- Initial --------
Ultimate.
2.2 Terminating traffic per line--CCS/BH: -------- Initial --------
Ultimate
2.2.1 Terminating will be made equal to originating if it is not
known to be different.
3. Subscriber Loop Resistance
3.1 Number of subscriber lines having loop resistance, including
the telephone set of:
No. of Lines
1501-1900 Ohms ----------
1901-3200 Ohms --------
3.2 Number of pay station lines having loop resistance, excluding
the telephone set, greater than:
No. of Lines
1200 Ohms (For Prepay) ------------
1000 Ohms (For Semi-Post Pay Operation) ----------.
4. Range Extension
4.1 If no standby power is available at the site, loop extenders
may be required on 1501 to 1900 ohms loops.
4.2 Loop extenders: Total Quantity ---------- By Bidder--Quantity
-------- By Owner--Quantity
(Explain in Item 12, Appendix B)
4.3 VF repeaters: Total Quantity ---------- By Bidder--Quantity ------
---- By Owner--Quantity ----------.
(Explain in Item 12, Appendix B)
5. Power Supply
5.1 Power Board.
5.1.1 The power board and associated wiring shall be of ample size
to meet the load requirements when this RST reaches -------- lines at
the ultimate anticipated traffic rates specified in Item 2, Appendix B.
5.2 Charger input rating shall be: Voltage ---------- Phase ------
---- Frequency ----------
3-Phase Connection:
3-Wire ----------
4-Wire ----------
Delta ----------
Y----------
5.2.1 Charger shall be capable of charging the RST battery on a
full float basis when the RST reaches -------- lines at ultimate traffic
rate specified in Item 2, Appendix B.
5.2.2 Charger shall be redundant --------.
5.3 Battery reserve shall be -------- busy hours when the RST
reaches -------- lines at the ultimate anticipated traffic specified in
Item 2, Appendix B.
5.4 Standby power is available. Yes ------ No ------.
5.5 Special equipment power requirements -------- amps.
5.6 Ringing.
5.6.1 Type of Ringing.
5.6.2 Frequency No....................... 1. 2. 3. 4.
Frequency HZ.............................. ..... ..... ..... .....
Max. No. Phones/Frequency................. ..... ..... ..... .....
5.6.3 Wattage to be sized for -------- lines.
5.6.4 Frequency Meter (see Item 12.3.3, Appendix A). Panel Mounted
------ Not Required ------.
[[Page 650]]
6. Emergency Operation
6.1 If path to central office is opened, the RST shall be able to
complete calls between subscribers in its own system: Yes ------ No ----
--
Further requirements should be listed under Item 12, Appendix B.
7. RST Distribution Frame Requirements
7.1 Total number of outside plant cable pairs to be terminated ----
--.
7.1.1 Gauge of outside plant cable pairs --------.
7.2 Number of outside plant cable pairs to be protected --------.
7.3 Number of additional protector pair units to be provided on MDF
--------.
Explain:
7.4 Main Frame Details
7.4.1 Present MDF to be reused Yes------ No ------.
If ``Yes'', Type --------.
Reused protectors are: -------- (Mfr.) -------- (Type).
7.4.2 Number of pairs of arrester units (switching equipment) ----
----.
7.4.3 Number of pairs of gas tube arrester units (special
equipment) --------.
7.4.3.1 Gas tubes to be: ------ light, ------ medium, ------ heavy,
------ maximum duty units.
7.4.3.2 Fail shorted/low breakdown failure mode required Yes ----
-- No ------.
7.4.3.3 Breakdown voltage of gas tube arresters --------.
7.4.4 Number of terminated pairs to be grounded --------.
7.4.5 Factory assembled tip cable Yes ------ No ------.
7.4.5.1 Tip cable length [if other than 20 feet (610 cm)] ------.
7.4.5.2 Tip cable formed Up ------ Down ------.
7.4.6 Pairs per vertical --------.
7.4.7 Height of vertical -------- feet -------- inches.
8. Building and Floor Plan Information
8.1 RST to be mounted in building ------.
8.1.1 Earthquake bracing required Yes ------ No ------ (see Item
14.3.6, Appendix A).
8.1.2 Supply building floor plan.
8.2 RST to be mounted in cabinet out of doors ------.
8.2.1 Cabinet to be mounted ------ on pole ------ on ground.
9. Subscriber Line Test
9.1 Remote testing of subscriber lines is required Yes ------ No
------.
9.2 Subscriber loop test set ------.
10. Span Lines to Host Central Office
10.1 To be supplied by Owner ------.
10.2 To be supplied by Bidder ------.
10.2.1 When the bidder is to supply the span lines, an RUS Form
397b, Trunk Carrier Systems, with the applicable parts completed must be
attached with a physical layout of the span line.
11. Grounding Considerations
11.1 The RST ground will be ------ ohms or less. (Refer to Item
4.6.3 of RUS TE&CM 810.)
11.2 This RST is considered to be in the following category for
lightning damage probability based on the Figure 1 map of RUS TE&CM
823.-------- Very High -------- Higher than Average -------- Average --
------ Lower than Average -------- Very Low
11.3 The following is additional information regarding operating
environment conditions which should be considered in determining system
protection requirements (tower in vicinity, high exposure, etc.):
12. Explanatory Notes
Appendix C to 7 CFR 1755.522--Specifications for Digital, Stored Program
Controlled Central Office Equipment Detailed Requirements--Bidder
Supplied Information
Telephone Company
Name____________________________________________________________________
Location
________________________________________________________________________
________________________________________________________________________
Central Office Name (By Location)
Town ----------
County ---------- State ------
________________________________________________________________________
Attended ------ Unattended ------
1. General
1.1 The equipment and materials furnished by the bidder must meet
the requirements of paragraphs (a) through (x), Appendix A, and Appendix
B of Sec. 1755.522.
1.2 Paragraphs (a) through (x) of Sec. 1755.522 cover the minimum
general requirements for digital, stored program controlled central
office switching equipment.
1.3 Paragraph (y) of Sec. 1755.522 covers requirements for
installation, inspection, and testing when such service is included as
part of the contract.
1.4 Appendices A and B of Sec. 1755.522 cover the technical data
for application engineering and detailed equipment requirements insofar
as they can be established by the owner. These appendices are to be
filled in by the owner.
1.5 Appendix C of Sec. 1755.522 covers detailed information on the
switching network equipment and the stored program controlled equipment,
and information as to system reliability and heavy traffic delays as
proposed
[[Page 651]]
by the bidder. This appendix is to be filled in by the bidder and must
be presented with the bid.
1.6 Appendix D of Sec. 1755.522 is the single-point grounding
system audit checklist.
2. Performance Objectives
2.1 Reliability (see paragraph (b) of Sec. 1755.522).
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.2 Busy Hour Load Capacity and Traffic Delay (see paragraph
(e)(10) of Sec. 1755.522. Describe basis for traffic analysis).
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
3. Equipment Quantities Dependent on System Design
3.1 Switch Frames and Circuits.
3.1.1 Number of Lines.
3.1.1.1 The number of lines to be provided shall include the number
required for the termination of subscriber lines, Item 7, Appendix A,
plus the number required for routine testing plus any additional to meet
the minimum switch increment of the selected system.
3.1.1.2 The number of lines provided for this office will be ------
3.1.2 Number of Ports Used for Trunks
3.1.2.1 The number of trunk ports to be provided shall be based on
the trunk quantities required (Item 8, Appendix A) as modified by the
minimum increment of the selected system. Provision shall be made for at
least 5 percent additional inlet and outlet ports over those required
initially. The additional ports shall be used for connecting additional
trunks that may be required in the future.
3.1.2.2 The number of trunk ports provided for this office will be
------------
3.1.3 Number of Subscriber Directory Numbers
3.1.3.1 The number of directory numbers provided shall be based on the
total directory numbers required (Item 6.1.11, appendix A), as
modified by the memory increment of the proposed system.
3.1.3.2 The number of subscriber directory numbers provided for
this office will be ------------
4. RST
4.1 Information for RST's must be supplied for each RST to be
furnished.
4.2 Number of line terminals for this RST will be ------------ .
4.3 Number of span line terminations to the central office being
supplied ------------ .
4.4 If the emergency operation option is required, it will provide
the following service when connection to the main office is severed:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
4.5 The ac power drain at the remote end will be:
Initial ------------ Ultimate ------------ Voltage: Single-Phase ----
-------- Three-Phase ------------
4.6 Special environmental requirements for the remote end:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
5. Power
5.1 AC Power Drain Watts
Initial ------------ Ultimate ------------
5.2 Heat Dissipation Watts
Provide the initial and ultimate equipment dissipation for each
equipment room.
5.2.1 Operating Temperature Range
Minimum ------------ Maximum ------------
5.2.2 Operating Humidity Range
Minimum ------------ Maximum ------------
6. Additional Information to be Furnished by Bidder
6.1 The bidder shall accompany its bid with the following
information:
a. Two copies of the equipment list and the calculations from which
the quantities in the equipment list are determined;
b. Two copies of the traffic tables from which the quantities are
determined, other than the full availability tables shown in paragraph
(p)(1)(i) of Sec. 1755.522;
c. Two copies of detailed switching diagram showing the traffic on
each route, the grade of service, the quantity of circuits, and main
distributing frames;
d. Block diagram of stored program control and associated
maintenance equipment;
e. A prescribed method and criteria for acceptance of the completed
central office, which is subject to review;
f. Location of technical assistance service with 24-hour
maintenance, and conditions when owner will be charged for access to the
service;
g. Calculations showing the method by which ringing machine sizes
were derived;
h. Precautions to be taken against static discharge;
[[Page 652]]
i. Details of central office grounding requirements, recognizing
local grounding conditions;
j. Details concerning traffic measurement capabilities and formats;
and
k. Details concerning AMA features and formats to be provided.
6.2 As a part of the response to the bid, the bidder must also list
information concerning the types and quantities of spare parts to be
furnished. All units, excluding those units described in paragraph
(x)(6)(i)(C) of Sec. 1755.522, must fall into one of the four classes.
The information must be in the following format:
----------------------------------------------------------------------------------------------------------------
Quantity of units in the CO's and RST's Quantity of spare parts furnished with
which are bid this bid
Unit No. Unit name -----------------------------------------------------------------------------------------
Class 1 Class 2 Class 3 Class 4 Class 1 Class 2 Class 3 Class 4
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
7. Explanatory Notes
Appendix D to 7 CFR 1755.522--Acceptance Checklist--Single-point
Grounding System
1. Approval Statement
Telephone Company:______________________________________________________
RUS Borrower Designation:_______________________________________________
RUS Contract Number:____________________________________________________
N/A_____________________________________________________________________
Name:
Central Office:_________________________________________________________
Remote:_________________________________________________________________
Date of Inspection:_____________________________________________________
Names of Inspectors:
Owner Representative____________________________________________________
Central Office Supplies_________________________________________________
Consulting Engineer_____________________________________________________
Mutually Approved Exceptions:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Grounding System Approval:
Name (Owner Representative)_____________________________________________
Signature_______________________________________________________________
Title___________________________________________________________________
Date____________________________________________________________________
Name (Supplier Representative)__________________________________________
Signature_______________________________________________________________
Title___________________________________________________________________
Date____________________________________________________________________
2. General Survey
2.1 This office is considered to be in the following category for
probability of lightning damage based on the Figure 1 map in RUS TE&CM
823 (also refer to paragraph (u)(2) of Sec. 1755.522)
---- Very High ---- Higher than Average ---- Average ---- Lower than
Average ---- Very low
2.2 Central office ground field (COGF) to be inspected for proper
bonding of conductors to ground rods, etc. COGF to earth grounding
reading is -------- ohms. (Refer to RUS TE&CM 802, Appendices C and D,
Measurement Techniques.) Is this resistance reading acceptable? (Refer
to RUS TE&CM 810, Items 1.6, 4.6.2 and 4.6.3 for protection
considerations.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.3 Ground connection to be inspected from the master ground bar
(MGB) to the central office ground field (COGF) to ensure it is properly
sized and installed by most direct route with no sharp bends. (Refer to
RUS TE&CM 810, Item 4.3.2 and section 8.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.4 Building structure grounds (steel rebar in footings, ironwork,
etc.) are to be properly bonded and connected to the MGB. (Refer to RUS
TE&CM 810, Item 4.3.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.5 Metallic central office door(s) are to be painted with metallic
paint with doorknobs left bare. Door(s) and frames are to be 00PAGE
P='739'grounded to the building structural ground or the MGB.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.6 Metallic fences within 6 feet (183 cm) of the exchange
building, storage facilities ground field, etc. are to be properly
bonded to the COGF outside of the central office building. Handhole
enclosure is to be used
[[Page 653]]
for the COGF connection to permit inspection and disconnect for earth
resistance testing. (Refer to RUS TE&CM 810, Appendix C, Item 4.6.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.7 Lightning rod systems are to be grounded by a separate
dedicated ground field. A bond should be provided between the COGF and
the lightning rod ground field. Handhole enclosure is to be used for the
COGF connection to permit inspection and disconnect for earth resistance
testing. (Refer to RUS TE&CM 810, Item 4.3.2.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.8 Radio/microwave tower ground grid is to be properly bonded to
the COGF by a direct outside connection. Handhole enclosure is to be
used for the COGF connection to permit inspection and disconnect for
earth resistance testing. (Refer to RUS TE&CM 810, Item 4.3.2 and
section 10.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.9 If a qualified metallic water system is present, inspect the
MGB connecting conductor to ensure that it is properly sized and
installed by the most direct route with no sharp bends and that it is
clamped solidly on the water pipes. (Refer to RUS TE&CM 810, Item 4.3.3
for details on metallic water system grounding.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.10 All power and grounding conductors are to be continuous, end
to end, with no splices, size discontinuity or intermediate
terminations. If an exception is necessary, unusual care must be taken
to assure proper bonding between the two sections. (Refer to RUS TE&CM
810, Appendix C, section 5.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.11 All ground conductors should be void of sharp bends along
their entire lengths. (Refer to RUS TE&CM 810, Item 8.2.2.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.12 Ground conductors should only be placed in nonmetallic
conduit. Those routed through metallic conduit require that both ends of
the conduit be bonded to the ground conductor. (Refer to RUS TE&CM 810,
Item 8.2.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.13 Ground conductors should not be encircled by metallic clamp.
Metallic straps are to be removed and replaced with nonmetallic clamps.
(Refer to RUS TE&CM 810, Item 8.2.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.14 If metallic conduit is used, it is to be insulated from all
ironwork.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.15 Inspect to determine if the required central office supplier
electrostatic discharge plates, wrist wraps, antistatic floor mats, etc.
are available and properly installed. (Refer to RUS TE&CM 810, Item
12.3.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
2.16 Ground conductors, except green wires, should not be routed
close and parallel to other conductors so as to minimize induction on
surges into equipment wiring. It is also better not to route these
ground conductors through cable racks or troughs, or within the confines
of any iron work. (Refer to RUS TE&CM 810, Item 8.2.3.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3. Master Ground Bar (MGB)
3.1 The designated P, A, N, and I segments of the master ground bar
(MGB) should be clearly identified. (Refer to RUS TE&CM 810, Figure 1
for MGB segmentation arrangement.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.2 Check for appearance and proper location of following on MGB:
[[Page 654]]
(a) R--Interior radio equipment \1\
---------------------------------------------------------------------------
\1\ Surge Producer--(P)
---------------------------------------------------------------------------
(b) C--Cable entrance ground bar \1\
(c) M--MDF ground bar \1\
(d) G--Standby power equipment frame ground \1\
(e) N--Commercial power MGN \2\
---------------------------------------------------------------------------
\2\ Surge Absorber--(A)
---------------------------------------------------------------------------
(f) B--Building structure ground \2\
(g) L--Central office ground field \2\
(h) W--Water pipe system \2\
(i) N\1\--Battery Return \3\
---------------------------------------------------------------------------
\3\ Grounds to non-IGZ Equipment--(N)
---------------------------------------------------------------------------
(j) N\2\--Outside IGZ: ------------\3\
(k) N\3\--Outside IGZ: ------------\3\
(l) I\1\--Ground window bar \4\
---------------------------------------------------------------------------
\4\ Grounds to IGZ Equipment (GWB's)--(I)
---------------------------------------------------------------------------
(m) I\2\--Ground window bar \4\
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.3 All connections to MGB are to be two-hole bolted down copper
crimped or compression type terminal lugs. (NOTE: No solder connections
are permitted.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.4 MGB is to be properly insulated from the mounting surface.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.5 All connections are to be tight.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.6 The MGB is to have an anticorrosion coating of the type which
enhances conductivity.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.7 Bar is to be clearly stenciled or legibly labeled ``MGB.''
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
3.8 All ground leads are to be properly sized and labeled as to
point of origin. (Refer to RUS TE&CM 810, Item 8.3.1 and section 8.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
4. Ground Window Bar (GWB)
4.1 All equipment grounds that originate inside of an Isolated
Ground Zone (IGZ) are to be terminated on the GWB which is preferably
located physically inside the IGZ and insulated from its support. (Refer
to RUS TE&CM 810, Item 5.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
4.2 Each GWB is to be connected to the MGB by the most direct route
with a conductor of 2/0-gauge or coarser, or resistance of less than
0.005 ohms. Parallel conductors for redundancy if required by the
supplier. (Refer to RUS TE&CM 810, Item 8.1.2.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
4.3 The metal framework grounds of only that switching equipment
and associated electrical equipment located inside of the IGZ should be
connected to the GWB as required by the central office equipment
supplier. (Refer to RUS TE&CM 810, Item 5.5.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
4.4 GWB is to be clearly stenciled or labeled ``GWB.''
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
4.5 All connections are to be tight.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
5. Isolated Ground Zone (IGZ)
5.1 IGZ areas are to be clearly marked on the floor or in some
other easily recognizable manner. (Refer to RUS TE&CM 810, Item 6.1.1)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
5.2 Confirm that all framework, cabinets, etc., within the IGZ are
ground connected only to the GWB. (Refer to RUS TE&CM 810, Item 5.5.)
[[Page 655]]
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
5.3 All cable racks, ground mats, switching and transmission
equipment within the IGZ are to have ground leads only to the GWB.
(Refer to RUS TE&CM 810, Item 5.5.2.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
5.4 Review ac power feed arrangement within the IGZ for acceptable
receptacle type and confirm that all green wires are properly connected.
(Refer to RUS TE&CM 810, Item 5.5.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
5.5 All ironwork, metallic conduit, and other equipment associated
with the switch are to be properly insulated at the IGZ boundary as
stipulated by the supplier. (Refer to RUS TE&CM 810, Item 6.2.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
5.6 With the GWB disconnected from the MGB, the resistance reading
of ------ ohms between the GWB and the MGB indicates adequate isolation.
(CAUTION: Test is to be conducted only with the approval and under the
direction of the central office supplier.)
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
6. Entrance and Tip Cables
6.1 When neither a cable vault nor a splicing trough exists, the
outside plant cable should be brought into the central office and
spliced to tip cables with a PVC outer jacket (ALVYNR) or
equivalent as close as practical to the cable entrance. (Refer to RUS
TE&CM 810, Item 7.3.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
6.2 All outside entrance cables and all tip cable shields are to be
separated by at least a 3-inch (7.6 cm) gap between shield ends.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
6.3 All entrance cable shields are to be bonded separately to
6 AWG or larger insulated wire or bonding ribbon and connected
to the Cable Entrance Ground Bar (CEGB) by most direct route with
minimum bends.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
6.4 Outside plant cable shields are to be connected only to the
CEGB, and the tip cable shields are to be connected only to the Main
Distributing Frame Bar (MDFB).
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7. Cable Entrance Ground Bar (CEGB)
7.1 The CEGB is to be properly insulated from the mounting surface.
(Refer to TE&CM 810, Item 4.2.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7.2 The CEGB is to be located as close as possible to the physical
ends of the entrance cable shields.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7.3 All connections are to use two-hole bolted down copper crimped
or compression type terminal lugs. (NOTE: No solder connections are
permitted.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7.4 All connections are to be tight.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7.5 Bar is to be clearly stenciled or legibly labeled ``CEGB.''
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7.6 All ground leads are to be properly sized and labeled.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
[[Page 656]]
7.7 The CEGB is to have an anticorrosion coating of the type which
enhances conductivity.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
7.8 The CEGB is to be connected to the MGB by a properly sized
conductor and by the most direct route. (Refer to RUS TE&CM 810, section
8.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
8. Main Distributing Frame (MDF)
8.1 RUS strongly recommends that MDF protectors be furnished
without heat coils. (Refer to RUS TE&CM 810, section 7.6.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.2 Incoming cable pairs terminated on MDF protector assemblies
should be protected with protector modules. These modules should contain
white coded carbon blocks or orange coded gas tube arrestors that are
included in the RUS List of Materials. (Refer to RUS TE&CM 810, Item
7.4)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
7______________________________________________________________________
8.3 All incoming subscriber cable pairs are to be properly
terminated at either a protector equipped terminal or connected to
ground.
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.4 MDF protector assemblies may be mounted directly on the
vertical frame ironwork. Protector assemblies on each vertical are
interconnected with each other and the Main Distributing Frame Bar
(MDFB) with a 6 copper grounding conductor. Alternative means
of connecting to the MDFB are also acceptable which do not rely on the
frame ironwork for conducting surge currents to ground. (Refer to RUS
TE&CM 810, section 7.)
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.5 Protective ``ground connections'' should be provided between
the MDFB and the frame ironwork for personnel protection regardless of
the type of protector assembly used. Protective ground leads should be
14-gauge, less than 12 inches (30.5 cm) in length with paint thoroughly
removed at point of connection to the ironwork. (Refer to RUS TE&CM 810,
Item 7.1.3.)
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.6 The MDFB should be insulated from the frame ironwork in all
cases where it is used as a Master Ground Bar (MGB). (Refer to RUS TE&CM
810, Item 7.1.2.)
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.7 Where the MDFB is used as the MGB in very small offices the
protective ``ground connections'' should be connected on the N section
of the bar. The MDF line protector assembly grounds should be connected
to the P section of the bar. (Refer to RUS TE&CM 810, Item 7.1.4.)
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.8 The MDFB is to be connected to the MGB by the most direct path
with minimum bends and proper conductor size. (Refer to RUS TE&CM 810,
Item 8.1.4.)
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.9 The MDFB should be free of all other ground leads when not used
as an MGB.
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8.10 Alternative arrangements which insulate the line protector
assemblies and MDFB from the frame ironwork may require a direct ground
connection of the frame ironwork to the MGB for personnel protection.
Conductor is properly sized and tightened with paint removal on main
frame ironwork at point of connection.
Acceptable: ---- Yes ---- No
Comments________________________________________________________________
________________________________________________________________________
________________________________________________________________________
9. Power Service Protection and Grounding
9.1 The ground conductor between the ac power system multigrounded
neutral (MGN) at the main ac disconnect panel and the master ground bar
(MGB) is to be properly sized
[[Page 657]]
and connected. (Refer to RUS TE&CM 810, Items 2.19, 4.3.1 and 8.1.3.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
9.2 If there is a non-MGN ac power system, there is to be a
properly sized and connected insulated conductor bond between the power
service ground electrode and the MGB. (Refer to RUS TE&CM 810, Item
4.3.1.1.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
9.3 AC conductors including ground conductors serving 120-volt ac
electric convenience receptacles and all direct wire peripheral
equipment, located in the IGZ, should be sized in accordance with normal
``green wire'' criteria. (Refer to RUS TE&CM 810, Items 5.5.4, 5.5.5,
and 5.5.6.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
9.4 Minimum protection for ac power serving the central office
buildings should consist of an RUS accepted secondary arrestor at the
service entrance. (Refer to RUS TE&CM 810, section 9.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
9.5 A properly sized conductor for ground bonding between the
standby power plant framework (not separately derived) and the MGB is to
be provided to equalize framework voltages for personnel safety reasons.
(Refer to RUS TE&CM 810, Item 4.2.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
10. Miscellaneous
10.1 All non-IGZ equipment frames, relay racks, cable racks and
other ironwork are to be properly connected to the MGB. (Refer to TE&CM
810, Item 4.4.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
10.2 Shields on high frequency intra-office cables are to be
properly isolated and connected only to an isolation ground bar in the
relay rack. All shielded cables entering the IGZ should only be
referenced at the IGZ termination point as given by the manufacturer.
(Refer to RUS TE&CM 810, Item 7.2.1.2.)
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
10.3 Isolation ground bars in the relay racks are to be properly
connected to the MGB with appropriate sized conductor with no sharp
bends.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
10.4 All radio equipment cabinet(s) are to be at least 10 feet (305
cm) from the IGZ.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
10.5 The metal spare parts cabinet is to be grounded with a
6 AWG or larger insulated wire to non-IGZ cable rack, etc. or
directly to the MGB.
Acceptable: ---- Yes ---- No
Comments:_______________________________________________________________
________________________________________________________________________
________________________________________________________________________
[58 FR 30938, May 28, 1993; 58 FR 36252, July 6, 1993; as amended at 60
FR 1711, Jan. 5, 1995, 60 FR 64312, 64314, Dec. 15, 1995]