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.