Avaya S8700 Maintenance Manual page 231

Automatic Transmission Measurement System
Singing return loss from 0 to 40 dB between the sum of the circuit (repeater) gains
SRL-LO
and the sum of the circuit losses. SRL-LO occurs most often in the frequency
range of 200 to 500 Hz.
Singing return loss from 0 to 40 dB between the sum of the circuit (repeater) gains
SRL-HI
on a circuit and the sum of the circuit losses. SRL-HI occurs most often in the
frequency range of 2500 to 3200 Hz.
Echo return loss from 0 to 40 dB between the level of signal strength transmitted
ERL
and the level of signal strength reflected. ERL occurs most often in the frequency
range of 500 to 2500 Hz.
ATMS Measurement Analysis
ATMS compares the results of the test measurements with threshold values to
identify trunks that are out of tolerance or unusable. Once a defective circuit has
been pinpointed, a proper analysis must be made to determine the appropriate
action to take on the facility failures. Although there is no "right" procedure for
every situation, the following items will help in troubleshooting problems:
If a circuit fails an ATMS transmission test, it does not necessarily mean
the trouble is in the facility itself. The problem could be caused by a faulty
test line, bad switch path, or a variety of other reasons.
If a circuit fails a transmission test but successfully passes a supervision
test, some of the items mentioned above are probably not at fault, since
proper call routing and circuit continuity are required for successful of a
supervision test.
If several circuits in the same group are failing, this could indicate the
failure of some common equipment (such as a carrier system, test line, or
cable) or erroneous information in the threshold tables.
When a test call can be successfully made, but not completed, either the
OTL or TTL is probably defective. For this failure type, further ATMS
testing might be seriously impaired, but the system is not otherwise
affected.
If a test call cannot be successfully made, the wrong number might have
been dialed, the far-end device might be busy, the far-end device is
defective, or there is a serious trunk failure obstructing the call.
555-233-143 Issue 1 May 2002 5-45