TDM-BUS (TDM Bus)
Issue 1 May 2002
8-1595555-233-143
If the backplane pins are not bent, run the test tdm P command to
determine whether the TDM-bus fault is still present.
a. If any of the TDM-bus tests fail, the problem is with another circuit
pack. Reinsert the originally suspected circuit pack, and repeat
Part 3 for the next circuit pack.
b. If not, replace the suspected circuit pack. The procedure is finished.
4. If every standby circuit pack has been tested but the TDM-bus failure still
exists, execute the reset pnc interchange and the set tone-clock
commands to put the currently active circuit packs into standby mode.
Repeat Part 3 of this procedure for each of the newly active circuit packs.
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 8-97). 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.