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Chapter 7
ISDN
The following provides information about using ISDN lines on your BCM system. Detailed
information about ISDN is widely available through the internet. Your service provider can also
provide you with specific information to help you understand what suits your requirements.
Refer to the following topics for information:
•
"ISDN hardware" on page 49
•
"ISDN standards compatibility" on page 51
•
"Planning your ISDN network" on page 52
•
"Supported ISDN protocols" on page 53
Types of ISDN service
Two types of ISDN services (lines) are available: Basic Rate Interface (BRI) and Primary Rate
Interface (PRI). Each line is made up of separate channels known as B and D channels which
transmit information simultaneously.
•
BRI is known as 2B+D because it consists of two B-channels and one D-channel.
•
PRI is known as 23B+D(in North America) or as 30B+D (in Europe). In North America,
23B+D consists of 23 B-channels and one D-channel (T1 carrier). In Europe, 30B+D consists
of 30 B-channels and one D-channel (E1 carrier).
B-channels: B-channels are the bearer channel and are used to carry voice or data information and
have speeds of 64 kbps. Since each ISDN link (BRI or PRI) has more than one B-channel, a user
can perform more than one transmission at the same time, using a single ISDN link.
D-channels: The standard signaling protocol is transmitted over a dedicated data channel called
the D-channel. The D-channel carries call setup and feature activation information to the
destination and has speeds of 16 kbps (BRI) and 64 kbps PRI. Data information consists of control
and signal information and for BRI only, packet-switched data such as credit card verification.
Note: Throughout this section, references are made to Service profile
identifiers (SPIDs). SPIDs are a part of the BRI National ISDN standard.
SPIDs are not used in the ETSI BRI standard or on PRI.
PRI services and features
The services and features provided over PRI lines include:
•
Call-by-call service selection (NI protocol)
•
Emergency 911 dialing, internal extension number transmission
•
access to Meridian 1 private networking (SL-1 protocol)
BCM 4.0 Telephony Device Installation Guide
47
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