ADTRAN DSU IV ESP, User Manual

Page: 120 / 194

Chapter 13. Testing and Troubleshooting
13-12 DSU IV ESP User Manual 61204011L1-1
DTE Only
The DTE O
NLY
test provides a method for testing both the DTE
interface drivers and receivers of the local DSU IV ESP plus its loop
transmitter and receiver. For this test, the loop transmit data is
connected to the loop receive data at a point close to the physical
network interface. This test can be used to verify proper operation
between the local DTE and the local DSU IV ESP.
Figure 13-7. DTE Only Test Diagram
Test Purpose
The DTE O
NLY
test is used for the following purposes:
• Verify integrity of the DTE interface.
• Verify integrity of connection between DTE and DSU IV ESP.
Interpreting Test Results
A BERT tester must be used to interpret the test results of a
DTE
O
NLY
test, because the BERT originates external to the local DSU.
When this test is implemented, the far unit receives an OOS/OOF mes-
sage from the network and enters an alarm state.
LOCAL
DSU/CSU
DTE
RD
TD
TELCO
NET Rx
NET Tx
DTE Rx
DTE Tx