User manual
DEFINITY ECS Release 8.2 Maintenance for R8.2csi 
555-233-119  Issue 1
April 2000
Maintenance for csi systems 
1-77Install DS1 CPE Loopback Jack (T1 Only) 
1
■ 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 
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 
as long as the tests for section 1 and section 3 pass. Since section 2 
includes the network interface point, it is necessary to work with the 
service provider to isolate the fault to the loopback jack cable, the “dumb” 
block, or the Smart Jack.










