DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Additional Maintenance Procedures
6-51Automatic Transmission Measurement System (ATMS)
6
ATMS Measurement Analysis
ATMS compares the results of the test measurements with threshold values to
identify trunks that are out of tolerance or unusa ble. Once a defec tive circuit has
been pinpointed , a proper analysis must b e made to determine the ap propriate
action to take on the facility failures. Althoug h there is no “right” procedure for
every situation, the following items will help in troubleshooting prob lems:
■If a circuit fails an ATMS transmission test, it does not necessarily mean
the trouble is in the facility itself. The problem c ould be caused by a faulty
test line, bad switch p ath, or a variety of other reasons.
■If a circuit fails a transmission test b ut successfully passe s a supervision
test, some of the items mentioned above are p robably not at fault, sinc e
proper call routing an d circuit conti nuity are required for succe ssful of a
supervision test.
■If several circuits in the same g roup are failing, this could indicate the
failure of some common equipment (su ch as a carrier system, test line, or
cable) or erroneous information in the threshold tables.
■When a test call can be suc cessfully made, but not c ompleted, 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 affec ted.
■If a test call cannot be suc cessfully made, the wrong number might have
been dialed, the far-end device might b e busy, the far-end devic e is
defective, or there is a serious trunk failure ob structing the cal l.
SRL-LO Singing return loss from 0 to 40 dB b etween the sum of the circuit
(repeater) gains and the s um of the circuit losses. SRL-LO occurs mos t
often in the frequency rang e of 200 to 500 Hz.
SRL-HI Singing return loss from 0 to 40 dB b etween the sum of the circuit
(repeater) gains on a circ uit and the sum of the circ uit losses. SRL-HI
occurs most often in the freq uency range of 2500 to 3200 Hz.
ERL Echo return loss from 0 to 40 dB between the le vel of signal strength
transmitted and the level of sig nal strength reflected . ERL occurs most
often in the frequency rang e of 500 to 2500 Hz