Pri Hardware; Bri Hardware - Nortel BCM50 Installation Manual

10

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 Enterprise Edge system is connected back-to-back with another switch using
a PRI link. If the other switch is loop-timed to your Enterprise Edge system, your DTM (PRI) can
be designated as a timing master.
If your Enterprise Edge 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
ISDN overview