Loopback Tests; Channel Bank: Normal Operation - Coastcom D/I Mux III System User Manual

This same sequence is identical for drop-and-insert and dual channel bank, and can also be performed
on LIU A. The payload, or test loop, is used to check the common equipment by looping the equipment
locally to the network through the LIUs.

Loopback Tests

The following sections describe, and depict, the various D/I Mux III system loopbacks. Refer to the
software diagnostics portion of this chapter for instructions on how to initiate and remove these
loopbacks.

Channel Bank: Normal Operation

In normal channel bank operation, only the T1-1 connection to the D/I Mux III shelf is used. The
Dual CSU Interface routes incoming Pulse Code Modulation (PCM) from span B to the input of
LIU B, and sends PCM from the output of LIU A to the output of span A. Channel cards can
transmit and receive on selected DS0 channels. Normal operation is represented in Figure 5-7.
Chapter 5. Diagnostics
Figure 5-7. Channel Bank: Normal Operation
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