ISDN Interface Types

The two primary ISDN user interfaces are the Basic Rate Interface (BRI) and the Primary Rate Interface (PRI). Both consist of several 64Kbps channels (Bearer or B channels) and one signaling channel (Data or D channel). ISDN B channels may be used for both dial-up voice and 64Kbps data connections. The ISDN D channel is a packet-switched channel connected to a separate packet network to which all users of ISDN are connected.

ISDN Basic Rate Interface (BRI)

The BRI interface consists of two 64Kbps B channels and one separate 16Kbps D channel. The D channel carries signaling, call set-up, control, and caller information. This configuration is often referred to as a 2B+D connection. This type of interface is capable of transmitting digital information at speeds up to 128Kbps.

ISDN Primary Rate Interface (PRI)

The PRI interface consists of 23 64Kbps B channels and once 64Kbps D channel (in the United States). This type of interface is often referred to as a 23B+D connection and is equivalent to the band width of a standard North American T1 interface. In Europe, the PRI interface consists of 30 64Kbps B channels and one 64Kbps D channel (30B+D) and is equivalent in band width to the standard European E-1 channel.

Last modified on February 4, 1996
Your Web Page Creator for this page is P. Allen Jensen.