Chapter 5. Loop Back and BERT Testing
94
November 2001
E1 line local digital loop back
E1 line local digital loop back is performed by connecting the E1
link receive signal to the output of the transmit path, in the DSU.
This loop back test checks the performance of the local ETU-
01A, the remote ETU-01A and the connections between them,
as shown in Figured 5-2.
Figure 5-2. E1 link local digital loop back
User
DTE
Data
Port
E1
E1 LINE
LOCAL ETU-01A
DSU
CSU