Coastcom D/I Mux III System

Chapter 5. Diagnostics
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Drop-and-Insert: Payload Loopback
Payload loopback is initiated from the D/I Mux III software interface. In payload loopback, the
LIUs are included in the data path; line loopback does not include the LIUs. In payload loopback,
the loopback occurs after rather than before the LIUs.
Drop-and-Insert: T1-1 Payload Loopback
Incoming PCM from span B is sent to the input of LIU B, then from the output of LIU B to
the input of LIU A, and finally from the output of LIU A to the output of span A. PCM from
the output of LIU B is also sent to the output of span B. Detail is depicted in Figure 5-16.
Figure 5-16. Drop-and-Insert: T1-1 Payload Loopback