Nortel BCM 3.7, Manual

Page: 864 / 1004

864 ISDN hardware
N0008589 3.3
• allows long distance carrier selection through user-dialed Carrier Access Codes
Consult your customer service representative to determine how your dialing plan is configured.
ISDN hardware
To support connections to an ISDN network and ISDN terminal equipment, your Business
Communications Manager must be equipped with a BRI S/T Media Bay Module (BRIM) or a
Digital Trunk Media Bay Module (DTM) card configured for PRI.
This section describes the hardware:
• “PRI hardware”
• “BRI hardware” on page 864
PRI hardware
The Digital Trunk Media Bay Module (DTM) is configured for PRI. In most PRI network
configurations, you need one DTM configured as PRI to act as the primary clock reference. The
only time when you may not have a DTM designated as the PRI primary clock reference is in a
network where your Business Communications Manager system is connected back-to-back with
another switch using a PRI link. If the other switch is loop-timed to your Business
Communications Manager system, your DTM (PRI) can be designated as a timing master.
If your Business Communications Manager has more than one DTM configured as PRI, you must
assign the first DTM as the primary reference, the second DTM as the secondary reference, and the
third DTM as the timing master.
If the system has a BRI module, it should be set as the timing master when a DTM in the same
network is defined as the primary reference.
BRI hardware
The loops on the BRI module can be programmed to support either network or terminal
connections. This allows you to customize your arrangement of lines, voice terminals, data
terminals and other ISDN equipment. This section describes some basic hardware configurations
for network and terminal connections for each loop type.
A BRI module provides four loops. Each loop can be individually programmed as:
• an S reference point connection (S loop) to ISDN terminal equipment (TE), or
• a T or S reference point connection (T loop or S loop) to an ISDN network using an external
NT1