Nortel BCM 3.5 Handbook - Digitcom

Telephony Hardware Components
The telephony components perform call processing and connect the BCM to the public switched
telephone network (PSTN) lines and to the BCM telephones. The main telephony hardware
components of the BCM system are:
• Media Services Card (MSC)
• Station Media Bay Modules
• Trunk Media Bay Modules
• Fiber Expansion Media Bay Module (BCM-FEM).
Media Services Card
With BCM Release 3.0, the Media Services Card (MSC) is now a field replaceable unit (FRU) to
allow businesses or users to replace this card in the field, as opposed to sending the entire system
in for repair. The MSC performs call processing and media processing of the voice channels. It
also provides the processing power for telephony functions independent of the Windows NTE
operating system. This means that if the NTE operating system should malfunction, the MSC can
still process telephone calls.
However, if Windows NTE is down for any reason, voice applications such as Voice Messaging
will not function. The MSC also provides the processing power for the voice channels and
compression utilities for Voice Mail, Call Center and IP telephony.
Installed on the MSC are two to four Processor Expansion Cards (PECs), which provide digital
signal processing (DSP) resource control. The PEC provides DSP resources to translate analog
and digital signals and process them into a format useable by the system. The DSPs support voice
applications, including voicemail, call center and IP telephony. All of these voice applications can
share the DSP resources on one BCM platform.
The BCM 3.0 platform comes equipped with two PEC IIIs on the BCM400 and one PEC III on
the BCM200. Depending on applications requirement, the BCM400 can be optionally equipped
with four PEC IIIs and the BCM200 can be optionally equipped with two PEC IIIs.
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