Nortel BCM50 2.0, Руководство по установке

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36 Chapter 5 ISDN overview
NN40020-309 NN40020-309
ISDN hardware
To support connections to an ISDN network and ISDN terminal equipment, your BCM50 must be
equipped with a BRI S/T Media Bay Module (BRIM) or a Digital Trunk Media Bay Module
(DTM) card configured for PRI. The digital BRI ISDN lines are connected to the BCM50b,
BCM50ba, and BCM50be main units through the BRI ports (RJ-45) on the front of the main units.
The following describes the hardware:
• "PRI hardware"
• "BRI hardware"
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 cannot have a DTM designated as the PRI primary clock reference is in a
network where your BCM50 system is connected back-to-back with another switch using a PRI
link. If the other switch is loop-timed to your BCM50 system, your DTM (PRI) can be designated
as a timing master.
If your BCM50 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.
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 one of the
following:
• an S reference point connection (S loop) to ISDN terminal equipment (TE)
• a T reference point connection (T loop) to an ISDN network using an external NT1
You can add integrated BRI lines on the BCM50a, BCM50e, and BCM50ae main units.
S Reference Point
The S reference point connection provides either a point-to-point or point-to-multipoint digital
connection between BCM50 and ISDN terminal equipment (TE) that uses an S interface. Refer to
Figure 8 .
Note: For information on adding integrated lines on an integrated router,
refer to the integrated router documentation.