Nortel Networks BCM200/400 User Manual

Page 54

Chapter 2 Introducing the BCM hardware

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If your system requires many IP lines or trunks, you can reduce the number of DS30 buses that are
assigned to MBMs and increase the number of buses available to IP telephones. This is known as a
3/5 DS30 bus split. In this case, you only have five DS30 buses available for use by the MBMs.
Refer to

“Understanding DS30 numbers” on page 111

for more information.

Figure 25 Telephony hardware components

The MBMs connect with external devices to implement various types of voice trunks and
extensions. Install the MBMs in the MBM bays in the BCM200 or BCM400 main units and the
BCM expansion unit.

MBMs have LEDs on the faceplate. For information on MBM LEDs, see

“Viewing the BCM

system LEDs” on page 79

The back of the MBM has a single connector that provides signaling channels, media channels,
and power to the MBM. This connector plugs into the MBM backplane in the main unit or
expansion unit. Some MBMs also have a cooling fan that runs off the MBM power source.

Figure

shows the rear views of the two types of MBMs.

Warning: Changing the DS30 bus split

If you change the bus split from 2/6 (default) to 3/5 after the system is initialized, any
module set to DS30 bus 7 or requiring the use of bus 7 becomes inoperable.

If you change the bus split from a 3/5 split to a 2/6 split after the system is initialized, all
data is lost, and all optional applications must be reinstalled and reconfigured.

Bus 7 must be

enabled

prior to converting from a 2/6 to 3/5 split.

Note: Refer to

“Media bay module availability” on page 361

to determine which

MBMs and which types of trunk lines are available in your location.

“Trunk media bay modules
(MBMs)” on page 55

“Station media bay modules
(MBMs)” on page 59

“Specialized media bay
modules (MBMs)” on page

“Telephones and adapters”
on page 75

Refer to