Operations Manual

glossary-2 © 1999 Triton Network Systems, Inc. All Rights Reserved.
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Add/Drop Multiplexer (ADM)
A device that provides an interface between the different signals in a digital
T-carrier or SONET network. When an ADM is inserted in a transmission
line, it enables lower rate signals to be extracted (dropped) and transported
differently (electrical or optical). Similarly, a lower rate signal can be inserted
(added) into a higher rate signal.
ADM
See Add/Drop Multiplexer (ADM).
AIS
See Alarm Indication Signal (AIS).
Alarm Indication Signal (AIS)
A special signal that is transmitted to downstream equipment for specific
equipment fault conditions.
antenna
A mechanical device that can convert electrical signals to and from
electromagnetic waves. An IFU contains an antenna.
Asynchronous Transfer Mode (ATM)
A cell-based protocol, developed by the ITU-T, for transmitting and
switching voice, video, and data traffic. ATM technology does not use a fixed
timing reference, hence the name asynchronous.
ATM
See Asynchronous Transfer Mode (ATM).
atmospheric absorption
Amount of energy lost when radio waves are transmitted due to the presence
of atmospheric gases.
attenuation
The reduction in the strength of a signal measured in dB. See also
propagation loss.
ADD/DROP
MULTIPLEXER
Signals added and dropped
at an intermediate point in
the transmission (via a
multiplexer)
Communication Flow