Troubleshooting
9-42 9161-A2-GH30-30
April 1998

Data Loopback

The Data Loopback tests the APM circuitry and the local loop connecting the port
to the CPE. The loopback occurs on the APM near the backplane connection,
toward the local loop.
98-15962
Network
Interface
All 1s
T1
NAM
OCU
APM
OCU
Port
Data
Loopback
The following tests are the only tests allowed to run at the same time as a Data
Loopback. No other tests can be running when a Data Loopback test is initiated:
Line Loopback on the cross-connected T1 interface
Payload Loopback on the cross-connected T1 interface
OCU-DP Remote Loopback Tests
The following remote loopback tests are available for the OCU-DP APM:
Latching Loopback – applicable only to the 64 Clear Channel DDS (64KCC)
rate
Nonlatching Loopback – applicable only to the DDS rates of 56K and
Switched 56
Device Tests
The T1 access unit supports a Lamp test at the device level. Use this test to
determine whether all LEDs are lighting and functioning properly. All LEDs light at
the same time every 1/2 seconds during execution of the Lamp test. When you
stop the Lamp test, the LEDs are restored to their normal condition. If the Test
Timeout configuration option is enabled and a Test Duration is set, the Lamp test
stops when the test duration expires. The Lamp test is not disruptive to data.