Cisco 1721 - Manual (Page 62)

Chapter 3 Troubleshooting
Problem Solving
3-12
Cisco 1721 Router Hardware Installation Guide
78-13834-02
• For routers with an ISDN U WIC, use the clear controller command to
terminate any active ISDN calls, to reset the ISDN BRI interface, and to reset
the ISDN line between the router and the central office switch. Do this for
each ISDN port installed in the router:
Router# clear controller bri0
Router# clear controller bri1
Table 3-4 lists troubleshooting methods for ISDN-related problems that
might occur.
Table 3-4 Troubleshooting ISDN
WIC Symptom(s) Check the Following Possible Causes
ISDN S/T Router is on,
but OK LED on
the card is off. • Is the OK LED on the
router front panel on? • If the OK LED is not on, the
router might be malfunctioning.
Contact your Cisco reseller.
• Are all ISDN cables
properly connected? • If the cables are properly
connected, the ISDN line might
be malfunctioning. Check with
your ISDN service provider.
• Is the NT-1 LED on? • If the NT-1 LED is not on, the
NT1 might be malfunctioning.
ISDN U Router is on,
but the NT-1
LED on the
card is off. • Is the OK LED on? • If the OK LED is not on, the
router might be malfunctioning.
Contact your Cisco reseller.
• Are all ISDN cables
properly connected? • If the cables are properly
connected, the ISDN line might
be malfunctioning. Check with
your ISDN service provider.
• Is the ISDN line
connected to the card
ISDN U port? • If the line is connected to the
port, the ISDN line might be
malfunctioning. Check with your
ISDN service provider.