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DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si
555-230-127
Issue 1
August 1997
Routine Maintenance Procedures
Page 5-81Install DS1 CPE Loopback Jack (T1 Only)
5
1. Test customer premises wiring (section 1 in Figure 5-14) from the ICSU to
the loopback jack as described in the “DS1 Span Test” section.
2. Test the loopback jack-to-”dumb” block and ”dumb” block-to-CO wiring
(section 2 in Figure 5-14
). This can be done using a loopback that
“overlaps” the section of the span. Any of the following loopbacks can do
this:
a. The local ICSUs line loopback, which is typically activated, tested,
and then deactivated by the DS1 service provider at the CO end.
b. The local DS1 interface’s payload loopback, activated and tested
by the DS1 service provider at the CO end.
c. The far-end ICSU’s line loopback. This test is activated at the
management terminal by entering test ds1-loop <location>
far-csu-loopback-test-begin. The test is terminated by entering
test ds1-loop <location> end-loopback/span-test. Bit error
counts are examined as described in the “DS1 Span Test” section.
This test only isolates problems to section 2 wiring if there are no
problems in the wiring between the far-end CO and the far-end
ICSU. Coordinate this test with the DS1 service provider.
If any of the above tests (a, b, or c) fail, a problem is indicated in
section 2. This could mean bad loopback jack -to-”dumb” block
cabling, but is more likely to indicate a problem somewhere
between the “dumb” block and the CO. This is the responsibility of
the DS1 service provider. If the DS1 Span Test confirms that there
are no problems in section 1, the technician should proceed as
follows to avoid unnecessary dispatch.
■ Identify and contact the DS1 service provider
■ Inform the DS1 provider that loopback tests of the CPE
wiring to the “dumb” block (section 1) showed no problems
■ If the far-end ICSU line loopback test failed, inform the DS1
provider
■ Request that the DS1 provider perform a loopback test of
their portion of the section 2 wiring by sending someone out
to loop section 2 back to the CO at the “dumb” block.
If this test fails, the problem is in the service provider’s
wiring.
If the test passes, the problem is in the cable between the
loopback jack and the “dumb” block. Replace the loopback
jack.