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Cisco 1721 Router Hardware Installation Guide
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Chapter 3 Troubleshooting
Problem Solving
Troubleshooting ISDN
Because ISDN uses many variables and supports many different configurations, it
sometimes can cause problems for the router. This section describes possible
problems related to the ISDN line.
Two commands are useful for troubleshooting ISDN:
•
For routers with an ISDN S/T WIC, enter the
clear interface
command to
terminate any active ISDN calls and to reset the ISDN BRI interface. Do this
for each ISDN port installed in the router:
Router#
clear interface bri0
Router#
clear interface bri1
Table 3-3
Troubleshooting the Power System
Symptom
Possible Cause(s)
Router shuts down after being on a
short time.
•
Make sure that the area in which the router is installed
meets the environmental site requirements in
Appendix A,
“Technical Specifications,”
in this guide.
•
If the front panel PWR LED is not on, the power supply has
failed.
The router attempts to boot, but all
LEDs remain off.
The power supply has failed.
The router is on, but the front panel
PWR LED is off.
The power supply has failed.
The front panel PWR LED is on, the
front panel OK LED is off, and the
router does not pass console or EIA
data.
The power supply has failed.
