61202.086L1-1 ISU 512 User Manual 61Chapter 7TroubleshootingIF SELF TEST FAILSWhen the ISU 512 powers up, it performs an internal self test. This takes ap-proximately 10 seconds. At the end of the test, the front panel displays SelfTest Passed. If Self Test Passed is not displayed, perform the following pro-cedure to verify if the problem can be solved locally:1. Ensure the ISU 512 is receiving power and is switched On.2. Turn Off the ISU 512; while holding the 0 key, power up the ISU 512. Con-tinue holding 0 for approximately 30 seconds, until the unit powers up.This resets all the internal settings to factory defaults and erases SPID andLDN information.3. If the ISU 512 still does not pass Self Test, call ADTRAN Technical Sup-port; see the inside back cover of this manual.IF AN ISDN NETWORK LINE READS DOWNIf EuroISDN switch type is selected and the front panel displays DOWN, it is only anindication that a call has not been placed to activate the line.When the ISU 512 has been set up, connected to ISDN lines, and the front paneldisplays DOWN for any of the network ISDN lines, use the following trouble-shooting procedure:1. Cycle power on the ISU 512, leaving it Off for a minimum of 2 seconds.2. If Ready is not displayed after waiting another full minute, disconnect theISU 512 from the ISDN line. Using a functioning voice phone, call the local
