CTC Union ETU-01A, Installation And Operation Manual

Page: 101 / 144

Chapter 5. Loop Back and BERT Testing
95
November 2001
E1 line local payload loop back
E1 line local payload loop back is performed by connecting the E1
link receive signal to the output of the transmit path, before the
Digital Service Unit (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 5-3.
Figure 5-3. E1 link local payload loop back
User
DTE
Data
Port
E1
E1 LINE
LOCAL ETU-01A
DSU
CSU