isr.co.ro : glossary (BRI) Basic Rate Interface The technical term for the normal ISDN (Integrated Services Digital Network) subscriber connection. A BRI link includes two "B" (bearer) channels that can transmit up to 64 kilobits per second each and a 16-kilobit-per-second "D" (data) channel used for control. Most ISDN configurations let you use one or both D channels at any one time--and charge you more if you use both. If you're located relatively close to the telephone company central office, a BRI connection can usually be installed using existing telephone wiring, but with changes in the circuitry at each end.