MMI-SYNC
Issue 1 May 2002
8-1129555-233-143
MMI-SYNC
NOTE:
Refer to Chapter 4, ‘‘Alarms, Errors, and Troubleshooting’’ for MMCH
troubleshooting information.
Each Port Network (PN) must have a TN787D or later MMI circuit pack assigned
as the Multimedia Interface (MMI) master synchronization source for that PN. If
one or more MMI circuit pack is administered in a PN, one MMI circuit pack is
designated as the master synchronization source for every MMI circuit pack within
that PN.
The MMI circuit pack generates a synchronization signal and puts that signal on
the TDM bus. Other MMI packs or any other circuit pack within a PN can listen to
this signal and “synchronize up” to it. The first MMI circuit pack inserted in a PN is
normally designated as the master. As subsequent MMI packs are inserted, they
are instructed to listen and synchronize to the time-slot of the master MMI. In the
unlikely case of an MMI losing this reference, an uplink message is sent from the
MMI circuit pack that lost the signal to maintenance, which also clears the “event”
counter on this MMI with a downlink message. This forces the MMI circuit pack to
return the current state of the synchronization signal. If the signal is still lost, then
the recovery algorithm is entered. Note that during this time, the MMI circuit pack
synchronizes to its internal clock, and there should be no service disruption. A
loss of synchronization is usually the result of a circuit pack failure. The
maintenance strategy is to switch the master source away from the bad pack to
another healthy MMI circuit pack within the PN.
MO’s Name (in
Alarm Log)
Alarm
Level
Initial SAT Command to
Run
1
1. Where UU is the universal cabinet number (1–64 for ATM PNC, 1–44 for CSS PNC); C is the carrier designation
(A, B, C, D, or E); SS is the address of the slot in the carrier where the circuit pack resides (01–21); and pp is
the 2-digit port number (01, 02, 03, ...).
Full Name of MO
MMI-SYNC MINOR test board UUCSS l r# Multimedia Interface circuit pack
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