Subscriber Lines Automatic Maintenance; Lcm Rextest - Nortel DMS-100 Series Maintenance Manual

Subscriber lines automatic maintenance

Automatic subscriber line tests are performed on line circuits and loops,
normally at normal scheduled intervals. These tests occur without switch
operator involvement, except for first scheduling. In a DMS-100 switch
office, the lines maintenance subsystem (LNS) performs these tests.

LCM REXTEST

For the LCM REXTEST, out-of-service diagnostics run for each LCM unit.
In-service diagnostics also run for each unit in normal and takeover modes.
The NODEREXCONTROL office parameter in table OFCVAR controls this
test.
The REx is performed during the specified interval for one LCM at a time,
in the order the LCMs are entered in the inventory table. Every LCM in the
office cannot be tested during the REx interval. When the next interval
starts, REx continues where the REx stopped during the previous interval. A
REx test on an LCM can take a maximum of 15 min to complete.
LCMREX test flow
A REX test for an LCM includes the following procedure:
1 If the two units of the LCM are in service, the following events occur.
Unit 0 becomes SysB, the system generates a PM128 state change log
with the reason
ISTb. The system also generates a minor alarm.
2 In-service diagnostics run on unit 1, which is in takeover. If diagnostics
fail, the unit is placed ISTb and the system generates a PM181 log.
3 Unit 0 is RTS. Out-of-service and in-service diagnostics run. If
out-of-service diagnostics fail, the unit remains SysB, the system raises a
major alarm, and generates log PM106. If the unit is RTS and the
in-service diagnostic fails, the unit is placed ISTb and the system
generates a PM181 log.
4 If unit 0 is RTS, these steps repeat for unit 1.
If a REX test fails, the system generates a PM600 log. The PM600 log
initiates a major alarm for the expanded peripheral module (XPM) that fails
the REX test. The major alarm appears at the MAP terminal under the PM
banner at the top of the display. The system generates a PM181 log after a
successful REX test.
If an INSV or OOS diagnostic test fails, the REx test failure reason includes
the mnemonic. A mnemonic is an easy-to-remember abbreviation. The
failure reason includes a mnemonic of the diagnostic that fails and the unit
that fails (0 or 1).
, and the LCM node status becomes
REX in progress
DMS-100 Family RLCM Maintenance Manual XPM12 and up
Maintenance overview 1-75