Troubleshooting 10-1
Chapter 10TroubleshootingThis chapter provides quick easy-reference troubleshooting tables for the Model XM128 ISDN
Digital Modem. For troubleshooting purposes, the Model XM128 modem performs its own
diagnostic tests, which can provide information about each of its functions.
The Model XM128 modem provides several diagnostic capabilities:
• Power-on self-test
• Local digital loopback tests
• Diagnostic command
• Modem reset
Power-on Self-test
At each power-up sequence or upon a reset command from the panel, the Model XM128 modem
tests the ROM code checksum, system RAM memory, EEPROM, digital and analog circuit
calibrations, and analog circuit calibrations.
Table10-1 summarizes the power-on self-test of the Model XM128 modem.
Table10-1. Power-on self-test
Test Sequence LED LNK LED B1 LED B2 LED AA Test Description
1 On Off Off Off Memory test
2 Off On Off Off ISDN chip interface te s t
3 Off Off On Off ISDN chip functional test
4 Off Off Off On HDLC function al test