tlantic (cable) to be determined transmission convergence TCP/IP transmission control protocol/Internet protocol time division duplex time division multiplex time division multiple access terminal equipment TelCo telephone company trees & growth token holding timer terahertz (1 X 1012 Hz) Telecommunication Industry Association test level point transport protocol data unit transmit reference equivalent token rotation timer time slot time slot interchanger time space time space (switching) tributary unit ACRONYMS AND ABBREVIATIONS tributary unit group telephone user part television valid transmission timer traveling-wave tube ultra-high frequency (300-3000 MHz) upper layer protocol universal mobile telecommunication system user-network interface user part user parameter control universal time universal time coordinated (coordinated universal time) unshielded twisted pair microsecond microvolt microwatt variable bit rate virtual container; virtual connection; virtual channel virtual channel connection virtual channel identifier voice frequency very high frequency (30-300 MHz) VHSIC very high speed integrated circuit very large scale integration virtual path virtual path connection virtual path identifier vertical redundancy check vestigial sideband voltage standing wave ratio virtual tributary wireless access communication system wide area network wave(length) division multiplex wireless LAN wireless local loop cross-modulation INDEX Boldface page number denotes in-depth coverage of a topic. Italic page number denotes a definition of a term. Page numbers followed by f denote figures. AAL. See ATM adaptation layer (AAL) advanced broadband digital transport formats, abort, 327 489-509 absolute delay, 47 SONET, 490-501 absolute level, 51 synchronous digital hierarchy, 501-508 access customer, 16 advanced mobile phone system (AMPS), 450, 458, access point (AP), 342 460, 469 access protocols, LAN, 298-308 Advanced Television Systems Committee (ATSC) ac circuits, 593-602 standards, 15, 420-422 with combined inductive and 