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

2-62 Functional overview
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Subscriber lines automatic maintenance

Automatic subscriber line tests occur on line circuits and loops. These tests
normally occur on a schedule. These tests occur without switch operator
involvement other than for initial scheduling. In a DMS-100 switch office,
these tests occur under the Lines Maintenance Subsystem (LNS).

LCM REXTEST

The LCM REXTEST consists of two funtions. This test runs out-of-service
diagnostics for each LCM unit and in-service diagnostics for each unit in
normal and takeover modes. The NODEREXCONTROL office parameter in
table OFCVAR controls this test.
The REX occurs during the specified interval for one LCM at a time. The tests
occur in the order the user enters the LCMs in the inventory table. The system
cannot always test each LCM in the office during the REX interval. When this
condition occurs, REX starts where REX stopped during the previous interval
when the next interval starts. The system takes a maximum of 15 min to
perform a REX test on an LCM.
LCMREX test flow
A REX test for an LCM includes the following procedure:
1. When both units of the LCM are in service, unit 0 is made SysB. The
2. In-service diagnostics are run on unit 1. Unit 1 is in takeover. When
3. Unit 0 is RTS. The system runs OOS and in-service diagnostics. When
4. When unit 0 is RTS correctly, the system repeats this procedure for unit 1.
When a REX test fails, the system generates a PM600 log. The PM600 log
initiates a major alarm for the XPM that fails the REX test. The major alarm
297-8361-550 Standard 04.02 December 2004
This test is not run on an LCM at the same time as an LCM audit and a
REX test.
The user must not enter BRTST_START_TIME and
BRTST_STOP_TIME fields of the
BICRELAY_XLCM_TEST_SCHEDULE office parameter with the same
value. A minimum of 10 min must separate these fields.
system generates a PM128 state change log with the reason REX in
progress. The LCM node status is made ISTb. The system generates
a minor alarm.
diagnostics fail, the system places the unit ISTb and generates a PM181
log.
out-of-service diagnostics fail, the system leaves the unit SysB. The
system raises a major alarm and generates PM106. When the unit is RTS
correctly and the in-service diagnostic fails, the system places the unit
ISTb. The system generates a PM181 log.