DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Additional Maintenance Procedures
6-15DS1 CPE Loopback Jack (T1 Only)
6
A problem can exist in 1 or more of th e 3 sections. The field technic ian is
responsible for finding and correcting problems in the first 2 sec tions. The DS1
service provider is resp onsible for finding and correcting p roblems in the third
section. Testing is divided into 3 steps.
■Test customer premises wiring (section 1 in the followi ng 3 figures) from
the ICSU to the loopback jack as described in “DS1 Span Test.”
■Test the CO-to-network interface wiring (section 3 in Figure 6-1) usin g the
Smart Jack loopbac k (CO responsibility). Coordinat e this test with the DS1
provider.
■Test the short length of customer premises wiring (section 2 in the
following 3 figures) between the l oopback jac k and the Smart Jack. This
can be done using a loopback that “overlaps” section 2 of the cable. Any
of the following loopbac ks can do this:
a. The local ICSUs line loopback, whic h is typically act ivated, tested,
and then deactivated by the DS1 service provid er at the CO end.
b. The local DS1 interface’s payload loopback, ac tivated and tested
by the DS1 service provider at the CO end.
c. The far-end ICSU’s line loopbac k. 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 desc ribed in “DS1 Span Test.” This test
method is the least preferable b ecause it covers wiring that is not in
the local portion of the sp an. This test only isolates problems to
section 2 wiring if there are no prob lems 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 ind icated in sec tion 2
as long as the tests for section 1 and section 3 pass. Since section 2
includes the network interfac e point, it is necessary to work with the
service provider to isolate the f ault to the loopback jac k cable, the “ dumb”
block, or the Smart Jack.