ital video, 57/14, 57/23 Network monitor, 61/12-16 factor, 10/14 theorem, 18/13-14 Networks/networking, 56/3-17 FDM transmission, 20/9-18, 20/20-1 architecture, 29/4-8 flicker, 10/11 OATS (Open Area Test Site), EMC, 23/13 ATM, 41/11 FM effects, 18/9-12 Object oriented software methods, 25/7, bridges,56/11-13 galactic, 27/5 development, 56/3-4 Gaussian, 4/9, 10/15, 20/10, 28/3-4 Obstacle gain, radio signals, 9/13 digital, 56/4-6 impulse, 10/11 OC (Optical Carrier), 42/17 digital networks, 29/10-12 intermodulation, 10/11 Octet, 19/12 Index/15 OCU (Office Channel Unit), TDM, 21/4 measurement and instrumentation, 7/4-9 PABX (Private Automatic Branch ODP (Open Distributed Processing), OSI, polarisation, 7/12 Exchange), radiometry and photometry, 7/3 cabling, 33/4 OFDM (Orthoganal Frequency Digital reflection, 7/11-12 call management, 36/3 Modulation), 57/3 spectrum, 7/3 calling and signalling, 31/6, 34/5-10, OFTEL (Office of Telecommunications) Optimal detection, 19/6 34/12-13 UK, 22/21 Optimality criterion, teletraffic, 5/5 cordless, 34/14-16 OHD (Over-the-horizon) radar, 9/7 Oracle, 57/14 data transmission, 34/14 Ohm's law, medium impedance, 6/3 Orbits, satellite see Satellites PMR with, 46/7 OIM (OSI Internet Management), 16/23 os (OutStation), multipoint systems, system and architecture, 34/3-5 OIW (OSI Implementors Workshop), 52/3-7, 52/7-8 voice processing with, 37/4-5 16/8, 22/14 OSF (Operations System Function), Packet switching, 3/3, 3/4, 35/5, 54/3-15 OLR (Overall Loudness Rating), 30/4, TMN, 16/17, 16/18 datagram networks, 54/12 30/5, 30/9 OSI (Open System Interconnection) error correction, 54/9-10, 54/11 Olympus satellite, 9/16 seven layer model, fast with SDH, 42/26 Omega navigation system, 9/6 layer 1, physical, 12/10, 44/7-9 flow control, 54/9-11 OMS (Operation and Maintenace testing, 61/24-30 monitoring and reporting, 61/12-15 Subsystem), AXE system, 32/16 layer 2, data link, 12/10, 44/9 multiplexing, 40/6, 40/9-10 On site paging, 45/4-5 testing, 61/30 network, 54/5-15,56/14 ONA (Open Network Architect