(analog wire-pair) transmission, 102 voltage values, PAM waveform, 109-111 VF trunks (junctions), loading, 103f volume unit (VU), 51 VHSIC (very high speed integrated circuit) decibels and, 621 video (television), as a QoS parameter, 45. See VP/VC switching hierarchy, 529f also television entries video compression, 421-423 standards for, 15 waiting systems (queueing), 63 video conferencing, frame transport for, 427-428. wander See also conference television in long-distance PCM transmission, 127 video multiplex coder, pX64 kbps codec, 427 slips due to, 139 video preprocessing, 422 watts, decibels and, 624-625 video source coding algorithm, 425 wave division multiplexing methods (WDM) video transmission, 404-406 over LOS microwave, 414-416 waveforms parameters in, 405-406, 409-410 digital data, 264-265 standards for, 411-413 neutral and polar, 259f virtual channel (VC), 528 waveform separation, 409 virtual channel connection (VCC), 528 waveguide dispersion, 243 setup and release of, 530 wavelength (2), 25h virtual channel identifier (VCI), 518 in fiber optics, 35 virtual connection, 318, 319 virtual container-n (VC-n), 503, 506-507 wavelength division multiplexing (WDM), 240-241 virtual path (VP), 528-530 virtual path connection (VPC), 529 weighting curve, 627, 628f virtual path identifier (VPI), 518 well-known sockets, 326 virtual tributary (VT) structure, 494-495 white noise, 48, 270, 627 virtual tributary frame sizes, 495f wide area networks (WANs), 291, 315-339 visual communication, 20 communication channels for, 548 VLAN2 tagging, 305 deployment of, 315-318 vocoders (voice coders), 468 frame relay and, 328-337 voice-band channel, 90-91 ISDN and, 327-328 voice channels packet data communications in, 318-319 amplitude distortion across, 46f in remote bridging, 310 analog, 89 TCP/IP and related protocols, 319-327 differential delay across, 47f wideband radio/coaxial cable systems, 187 decibels and, 625-630 window, 326 voice channel transmission, 118-119 wire diameter, measuring, 95 voice currents, 93 wireless, 2