Station Tests - Nortel DMS-100 Series Maintenance Manual

The LNS subsystem performs automatic line testing in a DMS-100 switch
office. The earlier figure shows the commands available at the ALT level of
the LNS level, which define the ALT. These commands are as follows:
The DIAGN command performs a complete diagnostic test on the line
card circuits. This command identifies defective line cards before the
defective cards generate customer reports. The DIAGN command uses
the line test unit (LTU) of the RLCM-EDC RMM to start tests. If the
LTU is not available, this command starts the no-LTU diagnostic.
The SDIAG command is a subset of the DIAG test and makes sure that
most of the line card circuits operate correctly.
The BAL command automatically sets the balance network in the line
card. This action provides transmission balance between the four-wire
side of the switch and the two-wire loop. The BAL command minimizes
subscriber reports of noise, echo, and garbled speech.
The LIT command starts an automatic test that detects cable pair faults.
Fault clearance must occur before these cables affect service and
subscribers report problems of a hum, noise, grounds, or a false ring trip.
The CKTTST command applies to loops using Meridian business sets
(MBS), data units (DU) associated with Datapath, asynchronous
interface modules (AIM), and IBERT line cards. The CKTTST
command performs circuit tests to confirm the ability of the set or line
card, or the set and line card. The CKTTST command also transmits and
receives messages correctly and adheres to message protocol.
The switch operator receives the lines, posted at the LTP, that fail to meet
standards of quality. The ALT log subsystem generates output reports that
also identify test results. After identification of the failures, test the lines
manually and correct the lines.

Station tests

Station tests are performed under the LNS subsystem at a MAP terminal.
Station tests are also performed for the Silent Switchman (SSMAN) and
Station Ringer (SR) tests. These tests are performed from a station. Stations
are tested manually.
The visual display unit (VDU) displays station test results. The VDU does
not display the results for the Station Ringer and Silent Switchman tests.
The test results are returned to the station.
Station tests determine if a station functions correctly when connected to a
loop and line circuit group.
Trouble isolation and correction 8-7
DMS-100 Family Maintenance Manual ABSK007