Adjuncts and Peripherals
DS1/T1 CPE loopback jack
826
SI Installation and Upgrades
June 2004
Figure 319: Network interface at “dumb” block with repeater line to fiber MUX for a 120A2
(or later) ICSU
Proceed as follows.
1
Test customer premises wiring from the ICSU to the loopback jack, as described in the “DS1 Span
Test” section.
2
Test the loopback jack-to-dumb block and dumb block-to-CO wiring (section 2 in
Figure 318
and
Figure 319
). 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 ICSU’s line loopback. Activate this test at the management terminal by
entering
test ds1-loop location far-csu-loopback-test-begin
, where
location
is
the DS1 interface circuit pack corresponding to the loopback jack. Terminate this test by
entering
test ds1-loop location end-loopback/span-test
, where
location
is the
DS1 interface circuit pack corresponding to the loopback jack.
Bit error counts are examined as described in the “DS1 Span Test” section. 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.
Figure notes
1
Span section 1
2
Span section 2
3
120A2 (or later) ICSU
4
RJ-48 to network interface (up to 1000 ft.
[305 m])
5
Loopback jack
6
Dumb block (demarcation point)
7
Repeater
8
Fiber multiplexer (MUX)
9
Central office
