1b-d Definition

Referring to a variation of the ITU-T specification for ISDN basic rate interface (BRI), also known as basic rate access (BRA). BRI supports two bearer (B) channels and one data (D) channel. Intended for applications that require only one information-bearing channel, perhaps for voice or data transmission, 1B+D supports one bearer (B) channel and one data (D) channel. The D channel is designated for signalling and control purposes, but also can be used for low-speed packet data applications such as transaction processing, credit card verification, and telemetry. See also 0B+D, BRI, and ISDN.