Administrator's Guide

B
Issue 5 October 2002 1957555-233-506
BLF
Busy Lamp Field
BN
Billing number
BOS
Bit-oriented signaling
BPN
Billed-party number
bps
See bits per second (bps).
bridge (bridging)
The appearance of a voice terminal’s extension at one or more other voice terminals.
BRI
The ISDN Basic Rate Interface specification.
bridged appearance
A call appearance on a voice terminal that matches a call appearance on another voice terminal for the dura-
tion of a call.
BTD
Busy Tone Disconnect
BTU
British Thermal Unit
buffer
1. In hardware, a circuit or component that isolates one electrical circuit from another. Typically, a buffer
holds data from one circuit or process until another circuit or process is ready to accept the data.
2. In software, an area of memory that is used for temporary storage.
bus
A multiconductor electrical path used to transfer information over a common connection from any of several
sources to any of several destinations.
business communications terminal (BCT)
A digital data terminal used for business applications. A BCT can function via a data module as a special-pur-
pose terminal for services provided by a processor or as a terminal for data entry and retrieval.
BX.25
A version of the CCITT X.25 protocol for data communications. BX.25 adds a fourth level to the standard
X.25 interface. This uppermost level combines levels 4, 5, and 6 of the ISO reference model.
bypass tie trunks
A 1-way, outgoing tie trunk from a tandem switch to a main switch in an ETN. Bypass tie trunks, provided in
limited quantities, are used as a last-choice route when all trunks to another tandem switch are busy. Bypass
tie trunks are used only if all applicable intertandem trunks are busy.
byte
A sequence of (usually eight) bits processed together.