 structure illustration, 282 GPRS, 232 Index in idle mode, 194-95 thermal, 157 transmitting power, 196-97 Nondispersion-shifted fiber See also Cellular networks (NZ-DSF), 175 Mobile switching centers (MSCs), 190 Nonreturn to zero (NRZ), 153, 154 gateway (GMSCs), 213 Nonuniform quantizing, 99-101 GSM, 213-14 defined, 99 HLR, 214 illustrated, 100 in incoming call, 196 See also Quantizing in outgoing call, 195-96 North American digital cellular VLR, 214-15 (NADC), 204-5 Modems, 177 North American PDH, 165-66 data compression, 266-67 defined, 165 defined, 262 illustrated, 166 dial-up, 267 See also Plesiochronous digital hierarchy error control, 266 (PDH) facsimile transmission, 267 Nyquist rate, 93 highest data rate, 265 interfaces, 266 Objectives, this book, xvii link over PSTN, 263 Offered traffic, 67 operation, 266, 267-68 Open Systems Interconnection. See OSI reference model standards, 263-64 V.90, 264, 265 Open-wire lines, 171 voice-band, 262-68 Operation and maintenance center Molina lost calls held trunking formula, 69 (OMC), 216 Multimode fibers, 173 Operation and maintenance (O&M), 59 Multiplexing, 158-70 Operator numbers, 32-33 FDM, 158-59 Optical amplifiers, 181-82 TDM, 158-59 Optical communications, 140-41 WDM, 179-80 Optical fiber cables, 172-75 advantages, 172-73 Network Control Protocol (NCP), 306 attenuation, 174 Network interface cards (NICs), 298 defined, 172 Network layer, 255-56 disadvantage, 173 defined, 255 dispersion principle, 174 protocol examples, 255-56 fiber categories, 173 See also OSI reference model illustrated, 172 Network management, 58-65 See also Transmission media DCN, 61-62 Optical line systems, 178-79 importance, 58-59 Optical technology, 359 introduction, 59 OSI reference model, 6, 248, 251-60 responsibility, 59-61 application layer, 259 TMN, 62-65 data link layer, 254-55 Network management site (NMS), 45 design, 251-52 Network node interfaces (NNIs), 344 illustrated, 252-53 Noise, 127 importance, 259-60 measurement, 148 network layer, 255-56 quantizing, 96, 97-99 physical layer