Avaya MCC1 Maintenance Procedures page 237

a Problems with the system clock (TDM-CLK) can cause service disruptions on the packet bus.
Every alarm active against TDM-CLK should be resolved first, even if the explanation refers only
to TDM bus. A packet-bus problem cannot cause a TDM-CLK problem, but a TDM-CLK
problem can cause a packet-bus problem.
b Throughout the flowchart, the question, "Are the packet-bus problems resolved?," refers to the
problems that led you to this chart, and can involve several checks, such as:
• Is every packet-bus alarms resolved?
• Is every packet circuit pack's port and endpoint alarm resolved?
• Is every ISDN-BRI station/data module, ASAI adjunct, system port supported adjunct,
and ISDN-PRI D-channel link in service?
• Does the Maintenance/Test packet-bus port (in normal or stand-alone mode) still indicate
a packet-bus fault?
c If only one PN is affected, its Packet Interface circuit is probably not causing the problem.
Nonetheless, if every ISDN-BRI and Universal DS1 circuit pack resides in the same PN:
• Assume that the answer to this question is "No."
• Check the IPSI's Packet Interface circuit in this PN.
d A packet problem affecting more than one PN is probably caused by either:
• IPSI's Packet Interface circuit fault
• IPSI-connected port network's packet bus fault
If there are IPSI-connected port networks, check the IPSI's Packet Interface circuit before
checking the packet bus.
e Because each PN's packet bus is physically separate, each affected PN must be checked
individually. (However, IPSI-connected PNs should be checked first. Once an IPSI-connected
PN's packet problem is resolved, any problems within it's scope are also usually resolved.) After
resolving the problem in one PN, verify that problems are also resolved in any other affected PNs.
f If a TN771D is absent, one must be installed to accommodate the stand-alone mode. See the
previous section on stand-alone mode.
g If a TN771D is present, it can fail in such a way that it eventually disrupts the packet bus or
misinterprets a packet-bus problem.
h If work is being done on-site, follow the procedures described earlier in this discussion on stand-
alone mode. If work is not being done on-site, go to the next step.
i The answer is "yes" if any of the following apply:
• The TN771D in stand-alone mode indicates any faulty leads.
• Test #572 in the PKT-BUS test sequence fails.
• The status port-network P display indicates that faulty leads are present, and the
TN771D in the PN is known to be functioning correctly.
j If the non-functional endpoints are isolated to a single circuit pack, then that circuit pack is
probably the cause of the problem.
Maintenance Procedures
December 2003
Packet and serial bus maintenance
Isolating and repairing packet-bus faults
237