andom routing, 5/13 Splitting, OSI layer services, 12/8 AFNOR (France), 22/21 Stirling's approximation, information SPM (Support and Peripherals Module), BSI (UK), 22/21-2 theory, 4/4 System 12, 32/10 CEN and CENLEC, 22/20-1 STM (Synchronous Transport Module), Sporadic E propagation, 6/21 CEPT, 22/15-16 SDH, 42/6, 42/12-15 Spot beam satellite antenna, 17/14 DIN (Germany), 22/21 STMR (SideTone Masking Ratio), 30/7 Spread spectrum systems, 14/12-13 DTI (UK), 22/21-2 Stochastic processes theory, 5/3 Sprint International, 11/7 ETSI, 22/16-19 Storage, video audio data, 57/28 SPS (Support Processor Subsystem), APZ European Community, 22/15 Store and forward networks see Packet subsystem, 32/17 NETs, 22/19-20 switching SPU (Supervisory Processing Unit), trade and user, 22/22-3 Stores, information capacity, 4/4 TXE4, 32/7 international, STP (Shielded Twisted Pair) cable, 33/4 SQL (Standard Query Language), 37/3 CCIR, 22/9-13 STP (Signalling Transfer Point), DMS, SQNR (Signal/Quantisation Noise Ratio), CCITT, 22/8-9 32/21 19/16-17, 19/20 IEC, 22/14 Strata graphs, 1/3 SSBSC (Single SideBand Suppressed ISO, 22/13-14 Strowger exchanges, 31/9-11 Carrier) modulation, 18/4-6, 19/7 ITU, 22/5-8 PABXs, 34/3 SSCP (Service Switching and Control trade and user groups, 22/14-15 Structural software testing, 25/15 Point) AXE system, 32/18 Japanese, Structured cabling, 33/1-10 SSID (Secondary Station Identifier), AOWS, 22/26 services handled, 33/3 PMR, 46/12 JISC, 22/26 Structured software design, 25/5-6, 25/8-9 SSMA (Spread Spectrum Multiple POSI, 22/26 STS (Space-Time-Space) switching, 31/15 Access), 13/15, 14/12 TTC, 22/26 Submarine fibre optic cables, 53/24 SSP (Service Switching Point), AXE New Zealand, Subscriber's distribution network, 29/5 system, 32/18 ITANZ, 22/27 Subscriber's line circuit see LC SSS (Subscriber Switching System), APT SANZ, 22/27 Subscriber's lines, attenuation, 29/8 system, 32/15-16 North American, Subscriber's private networks, 29/5 Stabilisation, satellite attitude, 51/8 ANSI (USA)22/24 Sunspots, 6/21, 27/6 