Rcs Fault Isolation Tests - Nortel DMS-100 Series Maintenance Manual

9-18 Trouble isolation and correction
Shelf alarm
A shelf alarm indicates a failure on a specified RCS shelf. This failure is
major and sets the RCS to ISTb. A LCGA, where the SMS detects a fault on
a DS-1 link, is an example of a fault that causes a shelf alarm. The types of
shelf alarms include A SHELF, B SHELF, C SHELF, and D SHELF.

RCS fault isolation tests

The following types of looping tests are supported:
PCM looping test
This test can run when a DS-1 channel is assigned to a subscriber in Mode
II. The SMS runs this test alone and checks the integrity of the assigned
DS-1 channel. For the PCM looping test the SMS sends three test words on
the DS-1 channel to the RCS. The SMS checks the looped return of these
test words from the RCS. If the test fails, the DS-1 channel is disabled and
the RCS is set to ISTb.
DDL looping test
The SMS runs this test alone, which tests the DDL link. In order to test the
DDL you must check the C field of the DDL. The SMS sends a message to
the RCS in the DDL and checks for a responding RCS message.
If either the DDL looping test or A-link fails, a major alarm occurs. The
RCS can continue to run because the other links continue to operate
correctly.
FELP command
The
channels on a DS-1 link to be looped at the RCS. During FELP, the system
loops all 24 channels on a DS-1 link from the SMS over the DS-1 link.
From the DS-1 link the 24 channels loop to the RCS and back to the SMS.
When the user issues the
one option from a set of four options. The option TEST is one of these four
297-8231-550 Standard 09.01 August 1998
Note: Alarm light emitting diodes (LEDs) light on the alarm control unit
(ACU) card when alarms occur on an RCS shelf. When faults are
corrected with the replacement of defective common equipment cards,
the LED turns OFF. Subscribers do not receive a dial tone immediately.
Dial tone occurs in 1 min after an audit that clears the alarm in the DMS
switch.
PCM looping test
Data description language (DDL) looping test
far-end loop (FELP) test.
command is a CARRIER-level command that enables all DS-1
>FELP
command for a carrier, the user must enter
>FELP