-bit envelope used to Bell (1982). Bell System Technical Reference, PUB 43801, Novem- frame six information bits. 21.8.3 AT&T's Accunet and BT's MegaStream Bocker, P. (1988) The Integrated Services Network, Springer Verlag Both Accunet T 1.5 and MegaStream are carrier transmission fa- (West Germany). cilities for high speed data and high volume speech communication- Bylanski, P. and Ingram, D.G.W. (1976) Digital Transmission S. The Accunet T1.5 facility operates at 1.544Mbit/s. The Systems, Peter Peregrinus, Stevenage. MegaStream facility operates at 2.048Mbit/s. Both facilities offer full or fractional T1/E1. CCITT (1989) Blue Books, Volume III - Fascicle III.4, General Data sources that can be effectively serviced by these trans- Aspects of Digital Transmission Systems - Terminal Equip- mission facilities include digital PABXs, analog PABXs with voice ments, Recommendations G.700 - G.795, CCITT, Geneva. digitisers, clustered terminals via multiplexer input, analog termina- tions, and video applications. Lucky, R.W., Salz, J., Weldon Jr, E.J. (1968) Principles of Data Communication, McGraw-Hill, New York. 21.9 References Matick, R.E. (1969) Transmission Lines for Digital and Communi- cation Networks, McGraw-Hill, New York. 8 Bit Envelope A = Alignment bit which alternates between 1 and 0 in successive envelopes to indicate the start and stop of each 8-bit envelope S = Status bit which is set or reset by the control circuit and checked by the indicator circuit I = Information bits Figure 21.15 KiloStream 8-bit envelope encoding Telecommunication standards Fraidoon Mazda MPhil DFH DMS MBIM CEng FIEE Northern Telecom Contents 22.1 The growth of telecommunication standards 22/3 22.2 The standards making process 22/3 22.3 International standards organisations 22/5 European standards 22/15 22.5 USA standards organisations 22/23 22.6 Canadian standards organisations 22/26 22.7 Japanese standards organisations 22/26 22.8 Australian standards organisations 22/26 22.9 New Zealand standards organisations 22/27 22.10 Biblio