Basic Rate Interface(BRI, 2B+D, 2B1D) An {Integrated Services Digital Network} channel consisting of two 64 {kbps} "bearer" (B) channels and one 16 kbps "delta" (D) channel, giving a total data rate of 144 kbps. The B channels are used for voice or user data, and the D channel is used for control and signalling and/or {X.25} {packet} networking. BRI is the kind of ISDN interface most likely to be found in residential service. (2002-01-13)