Cisco 1720 Hardware Installation Manual page 59

Chapter 3 Troubleshooting
Table 3-4 Troubleshooting ISDN
WAN Interface
Card Symptom(s)
ISDN S/T Router is on, but
OK LED on card
is off.
ISDN U Router is on, but
the NT1 LED on
card is off.
78-5405-03
Check the Following
• Is the OK LED on the
router front panel on?
• Are all ISDN cables
properly connected?
• Is the NT1 on?
• Is the OK LED on?
• Are all ISDN cables
properly connected?
• Is the ISDN line connected
to the card ISDN U port?
Cisco 1700 Router Hardware Installation Guide
Possible Causes
• If no, the router might be
malfunctioning. Contact your Cisco
reseller.
• If yes, the ISDN line might be
malfunctioning. Check with your ISDN
service provider.
• If no, the NT1 might be malfunctioning.
• If no, the router might be
malfunctioning. Contact your Cisco
reseller.
• If yes, the ISDN line might be
malfunctioning. Check with your ISDN
service provider.
• If yes, the ISDN line might be
malfunctioning. Check with your ISDN
service provider.
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