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61202.029L2-1 ISU 128 User Manual 77
Chapter 11
Troubleshooting
When the ISU 128 powers up, it performs an internal self test. This takes about
10 seconds. At the end of the test, the front panel displays Self Test Passed.
IF SELF TEST FAILS
If Self Test Passed is not displayed, perform the following procedure to verify
if the problem can be fixed locally:
1. Ensure that the ISU 128 is receiving power and is switched on.
2. Turn off the ISU 128. While holding down the 0 key, power back on. Con-
tinue to press 0 for 15 seconds. This will reset all the internal settings to
factory defaults.
3. If the ISU 128 still does not pass self test, call ADTRAN Technical Support
for assistance. See the back of this manual for phone numbers.
IF THE ISU 128 DOES NOT READ READY
When the ISU 128 has been set up and connected to an ISDN line but the front
panel does not read Ready after a few minutes, use the following trouble-
shooting procedure:
1. Cycle power on the ISU 128, leaving it off for a minimum of two seconds.
Turn the power on for one minute to ensure the unit does not read Ready.