TDM-BUS (TDM Bus)
Issue 1 May 2002
8-1113555-233-142
5. If the TDM-bus fault is still present, the suspected circuit pack was not the
cause of the TDM-bus failure. Do the following:
a. Remove the replacement circuit pack that was just inserted and
replace it with the previously suspected circuit pack.
b. Repeat Procedure 3 for the next circuit pack on the list for this
procedure.
If none of the TDM-bus tests fail, the procedure is completed.
If Procedure 3 fails to identify the cause of the problem, go to ‘‘Procedure 4:
Isolating TDM-Bus Failures to Carriers’’.
Procedure 4: Isolating TDM-Bus Failures to Carriers
Procedure 4 attempts to isolate a TDM-bus failure to a particular set of carriers.
Only the circuit packs in selected carriers are checked. Procedure 4 is used if the
preceding procedures fail, because it can help locate failures of:
■ Multiple circuit packs
■ The carrier’s hardware itself
In this procedure, the TDM/LAN cable assemblies and TDM/LAN bus terminators
are replaced.
If replacement does not resolve the TDM-bus fault, the cabinet is reconfigured so
that certain carriers are disconnected from the TDM bus. This is done by moving
the TDM/LAN bus terminators (ZAHF4) on the carrier’s backplane. To terminate a
TDM bus at the end of a particular carrier, the TDM bus cable that connects the
carrier to the next carrier should be unplugged and replaced with a TDM/LAN bus
terminator (see Figure 8-49). As the length of a TDM bus is modified, any
essential circuit packs to the system’s operation and TDM-bus maintenance (for
example, MSSNET and Tone-Clock), must still be connected to the shortened
TDM bus.
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