ion) and, 45 voice transmission and, 42-44 propagation velocity, 47, 377. See also velocity of propagation quantization, 426 in transmission-loss planning, 191-192 in pulse code modulation, 109-113 protective controls, 551 quantizing distortion, 112 protocol data unit (PDU), 281, 296, 297. See also quarter-CIF (QCIF) picture scanning format, 425 PDU structure quasiassociated mode, 362 protocols, 278, 388. See also data protocols; queue discipline, 63 internet protocol (IP); management protocols; queueing, 63 transmission control protocol/ internet protocol delays in, 394 (TCP/IP) data-link, 316 R-1 system, 155. See also link-by-link signaling functions of, 279-280 as noncompelled signaling, 158-159 media gateway controller, 395-400 R-2 code, line conditions for, 157. See also obsolete, 315 European regional signaling code (R-2 code) INDEX R-2 line signaling, 154 regenerative repeaters, 121-122 radian frequency, 268 jitter and, 127 radio, external synchronization via, 140 regenerators, 107 Radiocommunication Sector of the ITU (ITU-R), digital signal, 35 15, 458 Regional Bell Operating Companies (RBOCs), 16 radio distance, 198 register, 73 radio frequencies, 24. See also RF entries register occupancy time, 160 spectrum of, 25, 26f registration messages, 356-357 radio-frequency (RF) carriers, 80 reject (Rej) frame, 287 radio-frequency interference (RFI), 216-217 relative power level, 632-634 radio-frequency technologies, 344 relay, 23 radio horizon formula, 198 relay open system, 283 radio link, 36, 37f release dates, 542 radio propagation reliability, 213 mobile environment, 462-464 remote alarms, 122 models of, 463-464 remote bridges, 310 Radio Regulations, 15 remote monitoring (RMON), 558-559 radio specification, ground system mobile, 15 remote subscriber unit (RSU), 170 radio systems, 196-217, 457-487 feeds for, 171f, 172f cellular, 458-462 remote telephone switching, 74 cellular radio bandwidth, 468 remote terminal (RT), 128 cordless telephone technology, 481-483 repeaters, 242, 308-309 diversity and hot-standb