Interphase Tech RAS Communications Controller 5536 - Manual (Page 210)

Basic Rate Interface
190 Interphase Corporation
Basic Rate Interface
The ISDN Basic Rate Interface consists of three digital
channels: one D channel and two B channels. These channels
can be used simultaneously, and are often referred to as 2B+D.
Each ISDN B channel can be used separately to allow two
different connected users at the same time. The ISDN B
channels can also be combined to provide a total bandwidth of
128 Kbps.
Primary Rate Interface
The ISDN Primary Rate Interface, like BRI, has one D
channel, but it has more than two B channels. The number of
B channels for PRI differs in different locations.
• In North America and Japan, PRI consists of 24 digital
channels: one D channel and 23 B channels.
• In Europe and Australia, PRI consists of 31 digital
channels: one D channel and 30 B channels.
These channels can all be used simultaneously, and are often
referred to as 23B+D (North America and Japan) or 30B+D
(Europe and Australia).
Each ISDN B channel can be used separately to allow multiple
connected users at the same time. The ISDN B channels can
also be combined to provide a total bandwidth of 1472 Kbps
(North America, Japan) or 1920 Kbps (Europe, Australia).