ADTRAN 1200051L6 - Manual (Page 151)

61200051L1-1D ISU 2x64 Dual Port ISDN Service Unit User Manual 137
Glossary
asynchronous transmission
Not Synchronous. A method of data transmission which allows characters to be
sent at irregular intervals by preceding each character with a start bit and following
it with a stop bit. The timing of the transmission is not determined by the timing of
a previous character. Applications include communication between most small
computers (especially PCs) and mainframes, lower speed transmission, and less
expensive computer transmission systems. See Synchronous.
B-channel
64 kbps bearer channel used for voice, circuit, or packet switched data.
bandwidth
The range of electrical frequencies a device is capable of handling. The amount of
bandwidth a channel is capable of carrying tells you what kinds of communica-
tions can be carried on it. For example, a wide band circuit can carry a TV channel.
A wide band circuit that is capable of providing one video channel can also pro-
vide 1,200 voice telephone channels.
bearer service
As defined by CCITT standards, a type of telecommunication service that provides
the capability for the transmission of information between user-to-network inter-
faces. Bearer services defined for ISDN are circuit mode and packet mode.
BONDING mode 1 protocol
Industry standard B-channel aggregation protocol. Developed by the Bandwidth
on Demand Interoperability Group.
BRA
basic rate access. The BRA includes two 64 kbps B-channels and one 16 kbps D-
channel. Also known as Basic Rate Interface (BRI).
bridging
The technique whereby additional stations may be served from a two-point facility
by extending the facility from a bridge at one of the facility’s terminating points.