GL-12
Issue 9 October 1998
363-206-204
GLOSSARY
LOS
Loss of Signal — The complete absence of an incoming signal.
LR
Long Reach.
LS
Low-Speed.
N
Main
Two slots on the DDM-2000 OC-3 shelf in which the OLIU circuit packs are
installed.
Midspan Meet
The capability to interface between signals from two lightwave terminals of differ-
ent vendors. This applies to high-speed optical interfaces.
MD
Mediation Device.
MJ
Major Alarm.
MML
huMan-Machine Language defined by CCITT
MN
Minor Alarm.
MSDT
Multi-Services Distant Terminal.
MTBF
Mean Time Between Failures.
MTBMA
Mean Time Between Maintenance Activities.
Muldem
An older term for function group; now seldom used.
Multiplexing
The process of combining several distinct digital signals into a single composite
digital signal.