directivity, 6/11 ARQ (Automatic Retransmission AEIA (Australian Electronics Industries dual symmetric, 17/9-10 Request), Association), 22/26-7 earth station, 17/13-14 modems, 39/11 AEs (Application Entities), OSI, 16/9 efficiency, 17/4, 17/9-10 statistical TDM, 40/6-7 AFNOR (Association Francaise de gain, 6/10-11, 17/4, 17/9, 17/12, 50/5 ARS (Automatic Route Selection), Index/2 PABXs, 34/13 AUSTEL (Australian BER (Basic Encoding Rules), OSI, 16/9 ASCII 7 bit code, 40/4 Telecommunications Authority), 22/27 BER (Bit-Error Ratio), 28/7-8 ASEs (Application Service Entities), OSI, Authentication, EDI, 38/6-7 ATM, 41/19 Auto answer, modems, 39/11 audio digital companding, 57/16 ASK (Amplitude Shift Keying), 19/7-9, Auto call back, modems, 39/11 measurement, 61/7-10 19/10-11 Automated attendant, voice processing millimetre systems, 50/9 ASM (Analogue Subscriber Module), with, 37/4 optical receivers, 53/20-1 System 12, 32/8 Average mutual information, channel, 4/7 satellite systems, 51/16-17 ASN1 (Abstract Syntax Notation One), Average voice power-to-noise ratio, 50/11 Berlekamp/Massey algorithm, 14/9 OSI, 16/9, 16/11 Averages, 1/3-5 BERT (Bit Error Rate Tester), 61/7-8 Assembly languages, 25/12 AXE exchange system, 32/12-18 Bessel Functions, FM, 18/9-10 ASTIC (Anti-sidetone induction coil), BEXR (Basic Exchange Radio), rural 31/4-5 B7ZS (Bipolar 7 Zero code Suppression), multipoint, 52/8, 52/11 Astigmatism, eye, 7/11 TDM, 21/13 Beyond-the horizon propagation, 9/14-15 ASTRA satellite, 51/18 B8ZS (Bipolar 8 Zero code Suppression), BHCA (Busy Hour Call Attempts), 31/9 Asynchronous operation, modems, 39/5, TDM, 21/13-14 Bi-propellant satellite thrusters, 51/8 39/11, 39/12 B-ISDN (Broadband Integrated Services Billing, call management, 36/5 Asynchronous TDM see TDM Digital Network), 44/13-17 Binary symmetric channel, 4/8 AT&T, 11/6-7 ATM standards, 41/3, 41/8-18 Binomial distribution, 1/7 ATD (Asynchronous Time Division), 41/3 fast packet switching, 55/9 Birth-death models of queues, 3/7-8, ATM (Asynchronous Transfer Mode),