AT&T MERLIN LEGEND Communications System Release 2.0 Maintenance And Troubleshooting Manual page 204

Glossary
automatic-start tie trunk
A tie trunk on which incoming calls are routed to an operator or other
designated destination without a start signal. Also called automatic-ringdown
tie trunk or auto-in tie trunk.
auxiliary power unit
A device that provides additional power to the communications system.
B channel
A 64 kbps channel that carries a variety of digital information streams, such as
voice at 64 kbps, data at up to 64kpbs, wideband voice encoded at 64 kpbs,
and voice at less than 64 kbps, alone or combined with other digital
information streams. Also called bearer channel.
barrier code
A password used to limit access to the Remote Access feature of the
communications system.
basic carrier
A piece of hardware that holds and connects the processor; power supply;
and up to five modules in the communications system, See also expansion
carrier.
Basic Rate Interface (BRI)
A standard digital frame format that specifies the protocol used between the
communications system and a terminal. BRI runs at 192 kbps and provides
two 64-kbps voice or B channels and one 16-kbps signaling or D channel per
port. The remaining 48 kbps are used for framing and D-channel contention.
Behind Switch
A mode of operation in which the communications system control unit is
connected to (is "behind") another communications system.
BMI
Broadcast Music Incorporated
broadband
A transmission path having a bandwidth greater than a voice-grade channel.
BTMI
basic telephone modem interface
GL-2 Glossary