Avaya S8700 Maintenance Manual page 1064

Maintenance-Object Repair Procedures
This Loop Around test runs a series of individual tests on the two B channels (B1
and B2) associated with the port. It is a collection of the following:
Loop Around test across the TDM Bus for B1.
Conference Circuit test for B1.
Loop Around test across the TDM Bus for B2.
Conference Circuit test for B2.
The tests are run in the above order. If one fails, the remaining tests in the
sequence are not executed. An error code is returned at that point.
This test is not executed for ABRI-PORT/ATT-PORT/LGATE-PT/ATTE-PT
because the B channels associated with the port are not used by ASAI or Avaya
adjuncts.
The dotted lines in
performed for the B channels. The figure shows a terminal connected to a BRI
line board using a TN556. If a TN2198 is used the terminal would be connected to
a NT1, and the NT1 to the BRI board.
Figure 8-13. Path of the BRI Port Local TDM Loop Around
8-342 Issue 1 May 2002
Figure 8-13 on page 8-342
Tone
Generator
BRI Line
Board
show how a Loop Around test is
Tone
Detector
TDM Bus
555-233-143