zers, CATV, 439-440 extended binary-coded decimal interchange code equations, 607-611 (EBCDIC), 253f, 254 equipment. See also full equipment redundancy extended service set (ESS), 342, 343f call-setup, 160 extended subsplit frequency plan, 454 customer premise, 169, 195 extended superframe (ESF), 545, 547 data communication, 265-267 extended superframe groupings, 122 erbium-doped fiber amplifiers (EDFAs), 239-240, external synchronization, 139f, 140 240-241, 243 erlang, 7, 57 factors, in algebra, 605-607 Erlang, A. K., 57 fade margin, 213, 214 Erlang B loss formula, 61-63 fading, 212-215 Erlang C formula, 63 diversity technique for, 465-467 Erlang traffic formula, 61 mobile environment, 464-467 error accumulation, 127 out-of-phase conditions and, 214 error codes, SNMP, 557f variations in, 215 error control protocol function, 280 fan-out, 176 error correction, in frame relay, 511. See also error farad (F), 589 recovery; feedback error correction far-end crosstalk (FEXT), 128 error detection/correction signaling link layer, fast frequency-hop transceiver, 346 369-370 fault management, network, 540 errored second ratio (ESR), 199 FCS field, MAC frame, 302 errored seconds (ES), 142, 143, 199 FDM equipment, 84-85, 151, 153 error-free seconds (EFS), 143 FDM link, 80f error index field, in SNMP messages, 558 FDM systems error performance, 142-143, 254 employment and disadvantages of, 85 error rate, 120 level control in, 84-85 minimizing, 254 FEC block boundaries, MAC PDU, 351 error recovery, 328. See also error correction Federal Communications Commission (FCC), radio OSI model, 283 system regulation by, 196 errors feedback controls, 532 data-transmission, 254-258 feedback error correction, 257-258 detection and correction of, 255-258 feeder amplifiers, 439 types of, 255 feeders, 200 error status field, in SNMP messages, 557 fiber distributed data interface (FDDI) protocol, Ethernet, 300. See also CSMA/CD (carrier sense 306-308 multiple access/collision detection) LAN fiber-optic cable, 196 100-Mbps, 305-306 transmissio