Nortel Networks BCM200/400 - Manual (Page 108)

108 Chapter 8 Installing a media bay module (MBM)
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Figure 64 Process for determining MBMs
The first step in selecting the MBMs is to establish the number of extensions (internal lines) and
PSTN lines (trunk lines) you have or need. This step allows you to determine the number and type
of MBMs you require. The following sections describe how to determine which MBMs, and how
many, you require for your system.
• “Selecting trunk MBMs” on page 108
• “Selecting station MBMs” on page 110
• “Selecting a fiber expansion module (FEM)” on page 111
After you determine the MBMs required, calculate how the MBMs use the available system
resources. The following sections describe how the MBMs work within the available channels on
the media services card (MSC) in the BCM system.
Selecting trunk MBMs
The number and type of lines coming into your system determine which trunk MBMs, and how
many MBMs, you require to support your needs. Trunk lines come from the public network
(PSTN) or they support connections in a private network.
If you are setting up an entirely new system, perform a site survey to determine your current and
future needs. Nortel recommends that you perform the survey before you order any MBMs.
To select trunk MBMs
1 In Table 25 , record the number of each type of line you have. If you do not know the number
or type of lines you have, contact your service provider.
Note: If you plan to add any lines in the near future, include them in your initial estimates.
Determine DS30
requirements for
each MBM
Determine if any
offsets can be used
Set DIP switches on
MBMs
Install MBMs into the main
unit or expansion unit
Determine trunk
and extension
requirements
Determine which
DS30 buses are
available