 Mail), Centrex, videoconferencing, 57/33 pulse-compression systems, 9/8-9 see also Networks/networking; WANs swept frequency ground-based, 9/8-9 IXC (Interexchange) services, 11/7 LAPB (Link Access Protocol Balanced), Ionosphere, communication using, 9/6-7 J-net (Junction Network), DMS, 32/19 LAPD (Link Access Protocol Digital), D, E and F regions, 9/3-5, 9/6 Japan, telecommunications industry, 11/7 fast packet switching, 55/4 formation and structure, 6/20, 9/3-5 JIS (Japanese International Standards) PABXs, 34/7 monitoring, 9/8-10 mark, 22/26 statistical TDM, 40/7 NBS data transmissions, 27/5 JISC (Japanese International Standards Laplace transforms, 2/12-13 probing techniques, 9/7-10 Committee), 22/26 queuing theory, 3/9, 3/11 radio signals, Jitter, Laplace's law of insufficient reason, 4/4 effect on, 6/20, 9/5-10, 27/6-10 digital transmission, 28/13-16, 31/8 LAPM (Link Access Protocol for effect prediction, 9/10-11 digital video, 57/12 Modems), 39/8 IP (Internet Protocol), 16/19-20, 39/13 measurement, 61/6-7 Laser radar, 9/10 IPTM (ISDN Packet Trunk Module), TDM errors, 21/11-12 Lasers for optical fibres, 53/9-14, 53/21-2 System 12, 32/10 Johnson noise, 10/10 DFB (Distributed Feedback), 53/11 IPVC (International Private Virtual JTC1 (Joint Technical Committee 1), OSI Fabry Perot, 53/11 Circuit), 11/17 model, 16/7 light current characteristics, 53/12-13 IRFB (International Frequency JTM ( Job Transfer and Manipulation), stimulated emission, 53/9-10 Registration Board), 26/5 OSI, 16/11 turn on delay, 53/12-13 IRIM (ISDN Remote Interface Module), JTPC (Joint Technical Programming Layered architecture, OSI, 12/4-10 System1 12, 32/10 Committee) of ISO and IEC, 22/14 Layering, SDH, 42/21-2 Irradiance, 7/4 Junctions, telephone networks, 29/4 Layers, ISDN, 44/7-10 ISD (International Subscriber Dialling), LBA (Least busy alternative) routing, 29/12 k-Erlangian distribution, 3/6 5/13-14 ISDN (Intergrated Services Digital KADS (KBS Analysis and Design LC (Line Circuit), subscribers, 31/12 Network), 11/14-15, 29/11 Suppo