AT&T MERLIN LEGEND Release 3.1 System Planning Manual page 351

Glossary
Automatic Route
Selection
automatic-start tie
trunk
auxiliary power unit
B
B8ZS
backup
bandwidth
barrier code
basic carrier
baud rate
B-channel
Bearer-channel
Behind Switch
mode
See ARS .
Tie trunk on which incoming calls are routed to an operator
or other designated destination without a start signal, as
soon as the trunk is seized; the destination is specified
during programming. Also called "automatic ringdown" or
"auto-in" tie trunk.
Device that provides additional power to the system.
(bipolar 8 zero substitution) Line-coding format that
encodes a string of eight zeros in a unique binary
sequence to detect bipolar violation . See also bipolar
signal .
Procedure for saving a copy of system programming onto
a floppy disk or memory card . See also restore.
Difference, expressed in hertz, between the highest and
lowest frequencies in a range that determines channel
capacity.
Password used to limit access to the Remote Access
feature of the system.
Hardware that holds and connects the processor , power
supply , and up to five modules in the system. See also
expansion carrier .
Strictly speaking, a measurement of transmission speed
equal to the number of signal level changes per second.
In practice, often used synonymously with bit rate and
bps .
(Bearer-channel) 64-kbps channel that carries a variety of
digital information streams, such as voice at 64 kbps, data
at up to 64 kbps, wideband voice encoded at 64 kbps,
and voice at less than 64 kbps, alone or combined .
See B-channel .
One of three modes of system operation, in which the
control unit is connected to (behind) another telephone
switching system, such as Centrex or DEFINITY, which
provides features and services to telephone users. See
also Hybrid/PBX mode and Key mode .
GL–3
System Planning