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

Fault conditions

Several types of faults can occur in the components of the RLCM-EDC.
DS1 links from the LTC in the host office to the RLCM-EDC can become
faulty. If they do, messaging from the CC can be lost, and subscriber service
can also be lost.
A circuit card in the RLCM-EDC, including the power converter card, may
be faulty and may adversely affect subscriber service. RLCM-EDC
equipment, other than circuit cards, may also become faulty.
The RLCM-EDC P-side links carry messages that are vital to the
maintenance of subscriber service. A faulty peripheral side link may also
impact subscriber service.
The following sections discuss the specific fault conditions which occur in
RLCM-EDC components and the interfaces between RLCM-EDC
components.

LCA shelf failure

When a fault condition exists that causes one of the LCA units in the LCM
to go out of service, the in-service unit assumes control of the mate unit's
lines in addition to its own. This function, called takeover, is an automatic
maintenance feature of the LCM configuration. See "Takeover capability."
If any one of the following fails, the LCA shelf goes into takeover:
Note: As of XPM04 (and XPM03B) and the corresponding CM load, an
LCM unit is no longer SysB'd due to power converter failure (although it
must be ManB'd to replace the bad converter). The unit runs fine on power
from the mate converter.

Line drawer faults

A faulty bus interface card (BIC) or line card causes a faulty condition in a
line drawer. This fault is not sufficient to cause a takeover. If the BIC
problem is service affecting and the CM and LCM determine that the drawer
operates properly when under control of the takeover unit, one unit will be
SysB'd to preserve service to customers in that drawer. This only occurs if
both units are in service when the BIC problem was found.
NTX901AA: Local Features I
mate processor
digroup control card in the mate unit
mate LCC in the HIE shelf
Maintenance overview 1-53
DMS-100 Family Maintenance Manual ABSK007