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Primary Rate Interface and Basic Rate Interface.

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Posted by sagitraz

BRI & PRI

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Posted by waqasahmad

BRI
PRI

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Posted by crouse

Basic Rate Interface (BRI, which offers two B
channels and one D channel (2B+D).
Primary Rate Interface (PRI), which offers 23 B
channels and 1 D channel.

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Posted by sagitraz

B-channel
The Bearer ("B") channel is a 64 kbps channel which can be used for voice, video, data, or multimedia calls. B-channels can be aggregated together for even higher bandwidth applications.
D-channel
The Delta ("D") channel can be either a 16 kbps or 64 kbps channel used primarily for communications (or "signaling") between switching equipment in the ISDN network and the ISDN equipment at your site.

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Posted by elie

BRI
PRI

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Posted by robina

BRI and PRI

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Posted by waqqas1

The two types are BRI and PRI
BRI having data rate of 144 kbps
and PRI has 2.0 mbps

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Posted by HamidAliKhan

Integrated services digital network(ISDN) comprised of digital telephony and data transport services offered by regional telephone carriers.

ISDN invokes the digitization of telephone network which permits voice data,text,graphics & source materials transmitted over existing telephone wires.

ISDN applications include high speed image applications.
ISDN devices include terminals,TA(terminal adaptors).network termination devices,line termination equipment & exchange termination equipment.


ISDN offers two services
BRI(Basic rate interface)
PRI(Primary rate interface)

ISDN BRI Service offers two B channels and one D channel(2B+D).BRI B channels operates at 64kbps and used to carry user data.
BRI-D channels operates at 16kbps and used to carry control and signaling information.

ISDN PRI offers 23B and 1D channel (23B+1D)
,yielding a total bit rate of 1.544Mbps in North America and japan.
ISDN PRI in Europe,Australia and other parts of the world provide 30B channels plus one 64kbps D channel.

There are various specifications for layer 1, layer2 and layer 3 in ISDN.

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Posted by Hash007

ISDN channels are delivered to the user in one of two pre-defined configurations:

* Basic Rate Interface (BRI)
BRI is the ISDN service most people use to connect to the Internet. An ISDN BRI connection supports two 64 kbps B-channels and one 16 kbps D-channel over a standard phone line. BRI is often called "2B+D" referring to its two B-channels and one D-channel. The D-channel on a BRI line can even support low-speed (9.6 kbps) X.25 data, however, this is not a very popular application in the United States.

* Primary Rate Interface (PRI)
ISDN PRI service is used primarily by large organizations with intensive communications needs. An ISDN PRI connection supports 23 64 kbps B-channels and one 64 kbps D-channel (or 23B+D) over a high speed DS1 (or T-1) circuit. The European PRI configuration is slightly different, supporting 30B+D.

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Posted by jahangir1983