Coastcom D/I Mux III System

Chapter 5. Diagnostics
183
Drop-and-Insert: Normal Operation
Under normal drop-and-insert operation, the Dual CSU Interface routes incoming PCM from span B to
the input of LIU B, and sends PCM from the output of LIU B to the output of span B. Incoming PCM
from span A is sent to the input of LIU A, and PCM from the output of LIU A is sent to the output of span
A. That is, PCM coming in on span A is sent out on span A, and PCM coming in on span B is sent out
on span B. Channels from either span can be dropped (received) or inserted (sent) on the appropriate
line card of the D/I Mux III. D/I Mux III circuits can be inserted into either T1 span. Drop-and-insert in
normal operation is illustrated in Figure 5-11.
Figure 5-11. Drop-and-Insert: Normal Operation