Appendix D. Glossary
D-8 MX2800 STS-1 User Manual 61200659L1-1
LOS
Loss of signal. Defined as a line state in which no pulses are received for 175 bit
positions.
M13
DS1/DS3 multiplexer that combines up to 28 DS1 channels into one DS3 chan-
nel. Uses two-stage, bit synchronous TDM.
Mbps
Megabits per second (one million bits per second).
MIB
Management information base. A database of network management information
used by SNMP.
modem
Acronym for modulator/demodulator. Equipment that converts digital signals to
and from analog signals. Used to send digital signals over analog phone lines.
monitor
To watch or listen to a signal non-intrusively.
multi-point circuit
A single communications circuit that has more than two terminations.
NC
Normally closed. Relay switch contacts that remain closed when inactive.
near end
The unit on-site.
NI
Network interface. The demarcation point between the CPE and the PSTN.
NO
Normally open. Relay switch contacts that remain open when inactive.