Product specifications

Chapter 5.Loop Back & BERT Testing
58
May 2011
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
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
User
DTE
Data
Port
E1
E1 LINE
LOCAL ETU-01A
DSU
CSU