Glossary of Terms
L-O
L
LAN - Local Area Network A network designed to provide facilities for user communications within a defined building or plant and which does not necessarily use public service facilities or standards.
Leased line - A dedicated circuit, supplied by the PTT or other licensed operator, which permanently connects two or more user locations and is for the sole use of the subscriber.
M
MAPI - Messaging Application Programming Interface A Microsoft Windows interface.
MDF - Main Distribution Frame A wiring arrangement that connects outside lines on one side and internal lines from exchange equipment on the other.
MMI - Man Machine Interface Any procedure which allows a human operator to access and operate a system.
Modem - A device that modulates and demodulates signals transmitted over communications facilities. It is used to allow digital signals to be sent over analogue lines.
MTBF - Mean Time Between Failure The period of time that a system or device can be expected to work before a disabling fault occurs.
MTTR - Mean Time To Repair The average time required to return a faulty device or system to service.
Multiline group working - Each terminal can be a member of only one multiline group. All the terminals in that group must have the same key and lamp layout.
Multimedia - A combination of two or more media (i.e. voice, data, still image, video)
Multiplexer - A device that enables more than one signal to be sent simultaneously over one physical channel.
N
Network - A network provides users with communications links between different geographical locations.
Night service - The period outside normal working hours when the call centre is either directing or overflowing calls to another answering point.
NMS - Network Management System A system which monitors networked PBXs or keysystems and provides the network manager with information on traffic levels and congestion, fault management and call accounting.
Notification - The ability of a Voice Mail system to let you know when you receive messages in you mailbox.
NT1 - First customer premise device on a two-wire ISDN circuit coming in from the ISDN central office.
O
ODBC - Open Database Connectivity A Microsoft standard which allows databases created by various relational and non-relational database programs to be accessed by a common interface.
OSI - Open Systems Interconnection ISO's reference model for a seven-layer network architecture used for the definition of network protocol standards