ISDN BRI Trunk Introduction
Basic rate interface (BRI) is an Integrated Services Digital Network (ISDN) access method, typically used for home and small offices.
The BRI configuration provides 2 bearer channels (B channels) at 64 kbit/s each and 1 data channel (D channel) at 16 kbit/s. The B channels are used for voice or user data, and the D channel is used for any combination of data, control/signalling, and X.25 packet networking.