Diagnostic Tests For Lines; Channel Loss; Noise; Echo Return Loss - Nortel DMS-100 Series Maintenance Manual

Short term counters are reset (set to zero) inside on a unit base when a unit
correctly gains activity. This gain of activity can happen as a result of an
>RTS
from an XPM posted at the MAP terminal. When long term counters are
reset, the system generates a log with a summary of the data collected for
that node before the reset.
A BCS application resets all diagnostic history data that includes short and
long term failure counts. The system does not generate a log with long term
failure counts.

Diagnostic tests for lines

When the RCS line card is set up for testing, the following diagnostics can
occur.. These diagnostics occur as part of the
the LTP level.

Channel loss

The channel loss test is the same as the transhybrid loss test. The test checks
the PCM and analog path on a line card circuit. A TTU sends four ac
signals to a line card that has a reflect or reflect-NTPG termination
connected. These signals reflect to the TTU and the DMS-100 switch
analyzes the signals.
The channel loss test can occur with the ringing and coin return and collect
tests to determine if a correct termination is set up for these tests. For
example, if the absorb termination must be set up in the RCS line card, the
following condition occurs. The system must absorb the ac signals of the
channel test, with no signals returned to the DMS-100 switch.

Noise

Noise uses the TTU and a reflect or reflect-NTPG termination.

Echo return loss

The echo return loss test is the same as the flux cancellation test performed
on line module lines. The test checks the flux cancellation circuits of a line
card. The test uses the TTU and an absorb or absorb PTPG termination.
— the time when the last diagnostic failure occurred on unit 1
or command. Long term counters are reset on a node basis
>SWACT
DMS-100 Family SMS Maintenance Manual XPM10 and up
Trouble isolation and correction 9-53
command entered at
>DIAG