General Fault Correction Procedures; Maintenance/Test Circuit Pack (Tn771D) - Avaya MCC1 Maintenance Procedures

Packet and serial bus maintenance
Isolating and repairing packet-bus faults
These interactions allow normal non-packet system traffic to continue unaffected, and they reduce the
number of entries into the error/alarm logs. If the packet bus failure is caused by a failed circuit pack,
errors against the circuit pack should appear in the error/alarm logs as an aid for fault isolation. The above
strategy is implemented when:
• In-line errors indicate a possible packet bus failure reported by two or more packet circuit packs.
• A packet-bus uncorrectable report is sent from the Maintenance/Test packet-bus port (M/T-PKT).
When such a failure occurs, a PKT-BUS error is logged; see
information.

General fault correction procedures

This section gives an overview of the procedures used to isolate the cause and to correct packet bus faults.
Details are presented in following sections.
1 Procedure 1 attempts to determine whether a circuit pack that interfaces to the packet bus is the
cause of the packet bus problem. This involves examination of the error and alarm logs followed
by the usual repair actions.
2 If the packet bus problem persists, remove port circuit packs (those in purple slots) to look for
circuit packs that have failed and/or damaged the packet bus pins.
3 If the packet bus problem persists, perform the same procedure for control complex circuit packs.
4 If the problem persists, or if the packet-bus faults are known to have open leads, replace bus
terminators and cables. If this does not resolve the problem, reconfigure the carrier connectivity
of the PN to attempt to isolate a faulty carrier.

Maintenance/Test circuit pack (TN771D)

The TN771D Maintenance/Test circuit pack provides the following functions:
• Analog Trunk (ATMS) testing
• Digital Port Loopback testing
• ISDN-PRI Trunk testing
• Packet Bus testing
• Packet Bus reconfiguration (critical-reliability systems only)
Critical-reliability systems have a TN771D in each PN. A TN771D is optional in PNs of non-critical-
reliability configurations. The ISDN-PRI trunk testing functions are discussed in
Signaling Link
The digital port testing functions are discussed in:
• DIG-LINE (Digital Line)
• DAT-LINE (Data Line Port)
• PDMODULE (Processor Data Module) TDMODULE (Trunk Data Module)
• TDMODULE (Trunk Data Module)
• MODEM-PT (Modem Pool Port)
226
Port).
PKT-BUS (Packet Bus) for more detailed
ISDN-PLK (ISDN-PRI
Maintenance Procedures
December 2003