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432 Installing and Upgrading the Avaya G700 Media Gateway and Avaya S8300 Media Server
To test a loopback jack without a smart jack
1. Test customer premises wiring from the MM710 to the loopback jack, as described in
Testing the DS1 span from the loopback jack to the smart jack
on page 426.
2. Test the loopback jack-to-dumb block and dumb block-to-CO wiring (section 2 in Figure 42
and Figure 43
).
This can be done using a loopback that “overlaps” the section of the span. Any of the
following loopbacks can do this:
● The local ICSU’s line loopback, which the DS1 service provider at the CO end typically
activates, tests, and then deactivates.
● The local DS1 interface’s payload loopback, which the DS1 service provider at the CO
end activates and tests.
● The far-end MM710’s line loopback:
a. At the SAT type test ds1-loop location far-csu-loopback-test-begin
to activate this test,
where location is the DS1 interface circuit pack corresponding to the loopback jack.
b. Type test ds1-loop location end-loopback/span-test to terminate this
test,
where location is the DS1 interface circuit pack corresponding to the loopback jack.
Bit error counts are examined as described in Testing the DS1 span from the ICSU to the
loopback jack on page 421. 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.
Failure of any of these tests indicate a problem 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:
a. Identify and contact the DS1 service provider.
b. Inform the DS1 provider that loopback tests of the CPE wiring to the “dumb” block
(section 1) showed no problems.
c. If the far-end MM710 line loopback test failed, inform the DS1 provider.
d. 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.