Fault Conditions; Lca Shelf Failure; Line Drawer Faults; Link Failure - Nortel DMS-100 Series Maintenance Manual

package NTX154AA, Emergency Stand-Alone Operation to have ESA
capability.

Fault conditions

Several types of faults can occur in the components of the RLCM. In the
host office, the C-side links from the RLCM to the host LTC/LGC can go
down. If these network links have faults, a loss of messaging from the CC
and a loss of subscriber service can occur.
A circuit card in the RLCM, like the power converter card, can have faults
and can adversely affect subscriber service. The RLCM equipment, other
than circuit cards, can also have faults.
The RLCM P-side links toward the subscriber carry messages that are
important to the maintenance of subscriber service. A peripheral side link
that has faults can also impact subscriber service.
The following sections discuss the specified fault conditions which occur in
RLCM components and the interfaces between RLCM components.

LCA shelf failure

A fault condition can cause one of the LCA units in the LCM to go out of
service. When this problem occurs, the in-service unit assumes control of
the mate unit lines in addition to the in-service unit lines. This function is a
takeover and is an automatic maintenance feature of the LCM configuration.
Refer to "Takeover capability". If one of the following fails, the LCA shelf
goes to takeover:

Line drawer faults

A BIC or line card with faults causes a fault condition in a line drawer. This
fault is not severe enough to cause a takeover.

Link failure

Link failures include the following:
DS-1 links
Link failures are normally associated with the DS-1 interface cards in the
host controller, DS-1 link, or DS-1 interface cards in the RLCM.
mate processor
digroup control card in the mate unit
power converter in the mate unit
ANI and coin voltages in the mate ringing generator
mate LCC in the HIE shelf
DMS-100 Family RLCM Maintenance Manual XPM12 and up
Maintenance overview 1-43