61200051L1-1D ISU 2x64 Dual Port ISDN Service Unit User Manual 137Glossaryasynchronous transmissionNot Synchronous. A method of data transmission which allows characters to besent at irregular intervals by preceding each character with a start bit and followingit with a stop bit. The timing of the transmission is not determined by the timing ofa previous character. Applications include communication between most smallcomputers (especially PCs) and mainframes, lower speed transmission, and lessexpensive computer transmission systems. See Synchronous.B-channel64 kbps bearer channel used for voice, circuit, or packet switched data.bandwidthThe range of electrical frequencies a device is capable of handling. The amount ofbandwidth 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 serviceAs defined by CCITT standards, a type of telecommunication service that providesthe 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 protocolIndustry standard B-channel aggregation protocol. Developed by the Bandwidthon Demand Interoperability Group.BRAbasic rate access. The BRA includes two 64 kbps B-channels and one 16 kbps D-channel. Also known as Basic Rate Interface (BRI).bridgingThe technique whereby additional stations may be served from a two-point facilityby extending the facility from a bridge at one of the facility’s terminating points.
