Chapter 5. Diagnostics
186
Drop-and-Insert: T1-2 Line Loopback
Line Loop Set code received on the input of span A causes span A input PCM to be
looped back out span B before reaching the LIUs, as well as passing it on to the input of
LIU A. Output PCM from LIU A is sent to the output of span A. PCM from the input of
span B is unaffected, as shown in Figure 5-14. The output of LIU B is blocked.
Figure 5-14. Drop-and-Insert: T1-2 Line Loopback