Glossary

B channel A 56 Kbps or 64 Kbps bearer channel. Typically used for delivering data or voice over ISDN.

Bearer Service A type of telecommunications service that provides the capability to transmit a specific type of data such as voice or fax.

Bonding Bonding is the act of combining two 64 Kbps B-channels to derive a 128 Kbps channel. This is done by establishing two B-channel circuit-switched calls and combining them in the customer’s equipment (using Multilink PPP or the bonding specification) or by associating multiple B-channels in the network (multi-rate services).

BPV (BiPolar Violation) A BPV error event for an AMI-coded signal is the occurrence of a pulse of the same polarity as the previous pulse.

BRI (Basic Rate Interface) A defined ISDN interface that includes two B channels and one D channel. Also known as 2B+D. B channels are used for voice and data while the D channel is generally used only for signalling within the telephone network.

call bumping The ability to receive an incoming call during a bonded outbound call.

CCITT (International Telephone and Telegraph Consultative

Committee) See ITU (International Telecommunication Union) on page ITU (International Telecommunication Union).

Centrex Local Public Exchange with PBX facilities.

channel aggregation Channel aggregation combines multiple physical channels into one logical channel of greater bandwidth.

CO (Central Office) The site where the local Telco switches reside for all the telephone system’s call routing and other functions. This is the Telco side of the local loop. If the distance between your location and the central office switch exceeds 18,000 feet and/or the signal loss exceeds 35.0 dB, a repeater must be installed to allow ISDN service.

configuration cycle A type of I/O cycle provided on the PCI bus to facilitate system configuration.

CPE (Customer-Premises Equipment) All equipment that resides beyond the telephone service demarcation point. In the USA this typically includes the NT1 and all ISDN devices. Customer equipment may also include inside wiring, as well as telephone modems, ISDN equipment, and so on.

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