Adjuncts and Peripherals
DS1/T1 CPE loopback jack
824
SI Installation and Upgrades
June 2004
Figure 317: Network interface at extended demarcation point (smart jack accessible) for
a 120A2 (or later) ICSU
Testing a loopback jack without a smart jack
When the loopback jack is added to a span that does not contain a smart jack, the span is divided into 2
sections: from the ICSU to the loopback jack and from the loopback jack to the central office (CO).
Section 2 includes the short cable from the loopback jack to the dumb block demarcation point (part of
the loopback jack). This cable is the only part of Section 2 that is part of customer premises wiring. It is
not covered in the loopback jack’s loopback path. See
Figure 318
and
Figure 319
.
Figure notes
1
Span section 1
2
Span section 2
3
Span section 3
4
120A2 (or later) ICSU
5
RJ-48 to network interface (up
to 1000 ft. [305 m])
6
Dumb block (extended demarcation)
7
Loopback jack
8
Network interface smart jack
9
Interface termination or fiber multiplexer (MUX)
10
Central office
11
Dumb block to smart jack RJ-48
