Avaya S8700 Maintenance Manual page 2311

For multi-connect configurations

Hide thumbs Also See for S8700:

Table of Contents

TDM-BUS (TDM Bus)

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 the test tdm P

command. If any of the resulting tests fail, you must perform a manual TDM bus

isolation procedure to identify the cause of the problem.

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

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

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.

Issue 1 May 2002

Troubleshooting