, T1 and PCM-30 TDM, sound, 8/15 see also Radiowave propagation; Sky 21/11-12 suppressors/cancellers, 29/10 waves; Space waves; Surface waves Error detection/correction, talker/listener, 30/5, 30/9 Electromagnetism, fundemental laws, 6/3 modems, 39/11 ECITC (European Committee for IT Electronic Data Interchange see EDI packet switching, 54/99-10 Certification), 22/19 Electronic mail, 22/16 statistical TDM, 40/6 ECM (Error Correction Mode) facsimile Electrostatic discharge, 58/6 see also Codes/coding equipment, 60/9-10 ElectroStatic Discharge see ESD Error performance, ECMA (European Computer Electrostatic fields, 6/8 digital transmission, 28/5-9 Manufacturers Association), 22/22 Embedded KADS Systems, 25/7 monitoring, 40/15 ECSA (Exchange Carriers Standard EMC (ElectroMagnetic Compatiblity), rural multipoint, 52/10 Association), 22/25 circuit design and layout, 23/16-17 types of error, 14/4 ECSA (Exchange Carriers Standards equipment emissions, 23/12 ESD (ElectroStatic Discharge), EMC Association), 22/24 ESD, 23/11 effects, 23/11 ECTEL (European Conference of importance of, 23/10 ESF (Extended Superframe Format), Telecommunications Manufacturers), interference mechanisms, 23/15-16 21/8-9 legislation and standards, 23/12-15 ESN (Electronic Security Number), Index/8 PMR, 46/7 FACCH (Fast Associated Control FDM (Frequency Division Multiplex), ESO (European Standards Organisation), Channel), PCN, 48/8 20/1-22, 30/5 22/15 Facilities Management, SDH, 42/25 cable repeaters, 20/20-2 ESPA (European Selective Paging Facsimile (Fax), 39/13, 44/13 carriers, 20/7-8 Association), 45/6 64kbit/s equipment, 60/12-13 channels, groups and supergroups, 20/3-7 ESTI GSM PCN standard, 48/3 CCITT document, 60/5 companding, 20/17-18 ETACS (Extended TACS), cellphones, cellphones, 47/16 dBr, dBm and dBmO, 20/9 47/8, 47/8-9 G3 facilities, 60/3, 60/4, 60/5-14 frequency translation, 20/5-9 Ethernet, 13/3, 56/7 data compression, 60/6-8 integrated telephone networks, 29/10 TXE4 connections, 32/7 error detection/correction, 60/9-10 modulators/de