- Multichip module. archy in BT's network.) Micro-Cellular Networks. (Small cells used within Mobile Switching Centre. (Switching centre used in cellular radio networks to provide PCN-type ser- mobile radio systems.) vices.) MSDOS Microsoft Disk Operating System. (Very popular Maritime Communication System. operating system for PCs.) Mediation Device. (CCITT terminology for a device Medium Scale Integration. (Usually refers to an which carries out a protocol conversion function.) integrated circuit with a medium amount of on-chip Manual Digital Distribution Frame. circuit density.) Main Distribution Frame. Minimum Shift Keying. (A form of frequency shift Managed Data Network Service. (Earlier proposal keying, or FSK.) by CEPT which has now been discontinued.) Management System Management (Application) Member of the European Parliament. Entity. METEOSAT Meteorological Satellite. Mobile Satellite Service. METRAN Managed European Transmission Network. (CEPT Message Transfer Agent. (The item which relays, initiative to provide a broadband backbone across stores and delivers messages within a Message Europe.) Handling System, or MHS.) Multi Frequency. (A signalling system used with Mean Time Between Failure. (Measure of equip- push-button telephones.) ment reliability. Time for which an equipment is Mediation Function. (CCITT term for a function likely to operate before failure.) involving protocol conversion.) Managed Transmission Network. Modification of Final Judgement. (Delivered by Message Transfer System. Judge Harold Greene. 1982 act in the AT&T dives- Message Telephone Service. (US term for a long titure case.) distance telephone service.) Message Handling System. (International standard.) Mean Time To Repair. (A measure of equipment MegaHertz. (Measure of frequency. Equal to one availability. It is the time between an equipment million cycles per second.) failure and when it is operational again.) Management Information Base. (Refers to the col- Mobile Telephone Exchange. (Commonly used to lection of objects 