[Code of Federal Regulations] [Title 19, Volume 2] [Revised as of April 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 19CFR143.31] [Page 65] TITLE 19--CUSTOMS DUTIES CHAPTER I--UNITED STATES CUSTOMS SERVICE, DEPARTMENT OF THE TREASURY PART 143--SPECIAL ENTRY PROCEDURES--Table of Contents Subpart D--Electronic Entry Filing Sec. 143.31 Applicability. Source: T.D. 90-92, 55 FR 49886, Dec. 3, 1990, unless otherwise noted. This subpart sets forth general requirements for the entry of imported merchandise processed electronically through the Customs Automated Commercial System (ACS). Entries processed electronically are subject to the documentation, document retention and document retrievability requirements of this chapter as well as the general entry requirements of parts 141 and 142. Use of this system is voluntary and optional on behalf of the filer. Customs does not contemplate that processing of non-electronic filings shall be delayed.