Additional maintenance procedures
DS1 CPE loopback jack (T1 only)
366
Maintenance Procedures
December 2003
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 Span 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 Span 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 Span
Section 2 wiring by sending someone out to loop Span 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.
Configurations using fiber multiplexers
Use the loopback jack when customer premises DS1 wiring connects to an on-site fiber multiplexer
(MUX) and allows wiring to the network interface point on the MUX to be remotely tested. This requires
that ICSUs be used on DS1 wiring to the MUX.
Fiber MUXs can take the place of interface termination feeds as shown in
•
Figure 107, Network Interface at Smart Jack, on page 361
•
Figure 108, Network Interface at Extended Demarcation Point (Smart Jack inaccessible), on page
362
•
Figure 109, Network Interface at Extended Demarcation Point (Smart Jack accessible), on page
363
•
Figure 110, Network Interface at “Dumb” Block, on page 364
Test these spans using the same procedures as metallic spans. Note the following points:
1
Fiber MUXs may have loopback capabilities that can be activated by the service provider from
the CO end. These may loop the signal back to the CO or back to the DS1 board. If the MUX
provides the equivalent of a line loopback on the “problem” DS1 facility, this may be activated
following a successful loopback jack test and used to isolate problems to the wiring between the
loopback jack and the MUX.
Summary of Contents for CMC1
Page 1: ...Maintenance Procedures 555 245 103 Issue 1 1 December 2003 ...
Page 14: ...Contents 14 Maintenance Procedures December 2003 ...
Page 416: ...Additional maintenance procedures IP Telephones 416 Maintenance Procedures December 2003 ...
Page 426: ...Index X 426 Maintenance Procedures December 2003 ...
