BRI - This is the typical (basic) ISDN configuration. It consists of 2 'B' channels which can each carry digitized audio or data at a rate of 64 Kbit/s and one 'D' channel opperating at 16 Kbit/s for carrying data and signaling. This configuration is sometimes reffered to as 2B+D (two 'B' channels and a 'D' channel).