6. ABBREVIATIONS BCS Batch Change Supplement BERP Bit Error Rate Performance BMMI Bilingual Man Machine Interface CC Central Control CCS Common Channel Signalling CI Command Interpreter CM Computing Module CMC Central Message Controller CPSTATUS Call Processing Status CPU Central Processing Unit CR Carriage Return DS Data Store IOC Input Output Controller IOD Input Output Device MAP Maintenance and Administration Position MMI Man Machine Interface MS Message Switch MTC Maintenance NET Network NT Northern Telecom NTP Nothern Telecom Practice NM Network Module PEC Product Engineering Code PM Peripheral Module PO Purchase Order POP Performance Oriented Practices RTM Ready to Manufacture TC Terminal Controller VDU Visual Display Unit Page 51