CTC Union ETU-01A, Installation And Operation Manual

Page: 106 / 144

Chapter 5. Loop Back and BERT Testing
100
November 2001
Data Port V.54 remote loop back
The Data Port V.54 remote loop back is performed by sending
standard V.54 loop back codes to the remote unit. The remote
unit then connects its local data channel receive data (RD) to the
channel transmit input (TD). 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 5-8.
Figure 5-8. Data Port V.54 remote loop back
Integrated Bit Error Rate Test (BERT).
During Data Port BERT testing, the local DTE is disconnected
and the DSR line is off. An internal pattern generator connects a
user selected test pattern sequence to the transmit input of the local
data channel interface. To calibrate the system, the user can inject
errors at a selectable rate. The receive output is connected to a
pattern tester. The tester compares the received and transmitted
patterns and detects errors.
DTE
DSU
E1
CSU
LOCAL ETU-01A
DTE
DSU
CSU
REMOTE ETU-01A