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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 5-74Install DS1 CPE Loopback Jack (T1 Only)
5
Loopback Jack Fault Isolation Procedures
This section describes the possible DS1 configurations in which the loopback
jack may be used. These configurations are: when the DS1 provider includes a
Smart Jack, when no Smart Jack is provided at all, and when sites use fiber
multiplexers. These configurations are separated into “Configurations Using a
Smart Jack” and “Configurations Without a Smart Jack.”
Configurations Using a Smart Jack
The addition of the loopback jack and the presence of a Smart Jack divides the
DS1 span into 3 separate sections for fault isolation. These sections are shown in
Figure 5-11
through Figure 5-13 for the different span configurations. They are:
Section 1: Between the 120A2 (or later) ICSU and the loopback jack.
Section 2: Between the loopback jack and the Smart Jack (network interface
point).
Section 3: From the Smart Jack to the CO. It is necessary to contact the DS1
provider to run this test.
A problem can exist in 1 or more of the 3 sections. The field technician is
responsible for finding and correcting problems in the first 2 sections. The DS1
service provider is responsible for finding and correcting problems in the third
section. Testing is divided into 3 steps.
■ Test customer premises wiring (section 1 in the following 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 5-11) using the
Smart Jack loopback (CO responsibility). Coordinate this test with the DS1
provider.
■ Test the short length of customer premises wiring (section 2 in the
following 3 figures) between the loopback jack and the Smart Jack. This
can be done using a loopback that “overlaps” section 2 of the cable. 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 “DS1 Span Test.” This test
method is the least preferable because it covers wiring that is not in
the local portion of the span. This test only isolates problems to