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Communication Manager Maintenance-Object Repair Procedures
2238 Maintenance Procedures for Avaya Communication Manager 3.0, Media Gateways and Servers
TDM-Bus Fault Detection and Isolation
TDM-bus faults are usually caused by one of the following:
● A defective circuit pack connected to the backplane
● Bent pins on the backplane
● Defective bus cables or terminators
It is possible that a circuit pack can cause a TDM-bus fault and still exhibit trouble-free
operation. For example, insertions of any circuit pack into a slot with TDM bus terminations may
bend the backplane pins and short two leads together. Since the TDM bus is a shared resource,
identification of the cause of a TDM-bus fault can be difficult. If a TDM-bus problem is
suspected, run test tdm P. If any of the resulting tests fail, you must perform a manual TDM
bus isolation procedure to identify the cause of the problem.
!
WARNING:
WARNING: Since the procedure for isolating TDM-bus faults involves removing circuit packs
and possibly disconnecting entire carriers, the procedure is extremely destructive
to the port network that contains the TDM bus being tested. If possible, arrange
to perform this procedure at a time when traffic is minimal.
As circuit packs are removed or entire carriers are disconnected, any active calls terminating on
those circuit packs or carriers will be dropped. If you have any hints about a particular circuit
pack that may be causing the TDM bus problem investigate those before performing this
procedure (for example, look at any circuit packs that were inserted into the PN just before the
TDM bus problem appeared.
When straightening or replacing backplane pins in a carrier that contains a CFY1B Current
Limiter, power to the cabinet must be removed. When straightening or replacing backplane pins
in a carrier that does NOT contain a CFY1B Current Limiter, power to that carrier must be shut
off. Failure to follow this procedure may result in damage to circuit packs and power supplies,
and can be hazardous to the technician.
Note:
Note: Maintenance software requires TN748 or TN420 Tone Detector circuit pack to
test the TDM bus. Before starting these procedures, make sure that one of these
is installed in the port network being investigated.