Nortel Communication Server 100 Manual page 167

The system loopback test is not service-interrupting. However, if carrier 2
is not a spare carrier but a primary carrier, the system can respond with
error message BSD202 if the TEST ALL command is executed in LD 45.
To avoid this problem, do not perform the TEST command manually on
the system that has one or more Carrier Remote superloops with carrier
#2 configured as an active carrier.
Loopback tests check the continuity between various interface points in
the system. This is performed by sending a known signal pattern from the
originating point to the destination and receiving it back at the originating
point or a designated detecting point. If the pattern is detected, and it
matches the transmitted pattern without errors, the test verifies that the
tested equipment and their connections are operating correctly. However,
if the pattern is not detected or it is detected with errors, the equipment or
the connections between the equipment are faulty.
The difference between loopback tests for the Carrier Remote IPE and
the Superloop Network and Peripheral Controller cards is the selection
of specific timeslots that have to be assigned for the Carrier Remote IPE
loopback testing.
The system loopback test also tests the superloop network switching
functions and the peripheral controller loopback functions on the Local
Carrier Interface card and the Remote Carrier Interface motherboards
respectively. The on-line test 1, using the MMI command, tests the
loopback between the daughterboards of these two cards.
The loopback uses the Local Carrier Interface card as a pattern generator
and detector. For example, the signal is transmitted by the Local Carrier
Interface card to the Remote Carrier Interface card and looped back to the
Local Carrier Interface card over the carrier links.
Note:
For a Carrier Remote IPE with a spare link, the loopback is
automatically routed over the functioning carrier link, not the faulty link.
To identify the carrier that may be faulty, perform the carrier test at each
end of the link by following the instructions in step 4 of
"Performing the Local Carrier Interface card self-test" (page
Figure 24 "Loopback path for XCON test 6" (page 168)
loopback path and shows the Local Carrier Interface card as a test pattern
generator and detector.
Nortel Communication Server 1000
Carrier Remote IPE Fundamentals
NN43021-555 04.01 4 June 2010
Copyright © 2007-2010 Nortel Networks. All Rights Reserved.
Carrier Remote IPE fault isolation and correction 167
Procedure 38
165).
illustrates the