AT&T MERLIN LEGEND Installation & Maintenance Manual page 688

Glossary
B
B channel
For an Integrated Services
Digital Network (lSDN), a
64-kbps channel that carries
a variety of digital information
streams, such as voice at
64-kbps, data at up to
64 kpbs, 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.
bandwidth
The difference, expressed in
hertz, between the highest
and lowest frequencies in a
range of frequencies that
determine channel capacity.
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 module; power
supply module; and up to five
line, trunk, or station modules
in the communications
system. See also expansion
carrier.
Basic Rate Interface (BRI)
A standard Integrated
Services Digital Network
(ISDN) 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.
baud
In telecommunications
applications, a unit of
transmission speed equal to
the number of signal events
per second. See also bit rate
and bits per second.
Behind Switch
A mode of operation in which
the communications system
control unit is connected to
(is "behind") another
communications system.
binary code
An electrical representation of
quantities or symbols
expressed in the base-2
number system.
Glossary GL-3