Coastcom D/I Mux III System User Manual

Chapter 5. Diagnostics
181
Channel Bank: Line Loopback
Line loopback is set in response to receiving the “Line Loop Set” code on a span's input, or via
software. Pulse Code Modulation (PCM) arriving at the input is looped back to the opposite
span's output. Figure 5-9 illustrates PCM looping back from span A’s output, as a result of a Line
Loop Set code received by span B’s input. PCM is also passed on to the LIU B input, even
though the LIUs are not in the PCM path. T1 line receivers and line buildouts are kept in the
PCM loop to maintain the proper T1 line levels. Figure 5-9 shows the path of the line loopback
signal.
Figure 5-9. Channel Bank: Line Loopback

Coastcom D/I Mux III System Specifications

General

Brand	Coastcom
Model	D/I Mux III System
Category	Multiplexer
Language	English