No Dial Tone

Troubleshooting No Dial Tone on VoIP Networks


First, verify whether you can connect to the web; many VoIP networks use the same data connection you use to connect to the internet. Typically, if there is a problem with your internet connection (for instance, an outage or power loss), the same problem will affect your phone system as well. A simple modem reboot can resolve simple issues, and we recommend doing this about every 30 days to keep the system healthy; you can do this by unplugging the modem from power for about 10-15 seconds. Please note this will take your system offline for up to 5 minutes.

Wireless Routers and Firewalls

If the modem has power, but is still not connecting to the web, you may also need to reboot any wireless routers or firewalls also attached to the modem. Beyond that, if you are still unable to connect to the internet and your phones are still without dial tone, you will need to reach out to your internet service provider to determine if there are any outages in the area, or if the modem needs to be replaced.


ADTRAN has power and that all of the cables in back are seated properly. Note: an ADTRAN is a type of router that enables phone calls to go over the internet. It is usually a flat gray box about the size of a DVD player and is typically plugged via ethernet into the back of the modem. You can reboot this device in the same manner you rebooted the modem; unplug the ADTRAN from the power socket, wait 10-15 seconds, and plug them back in. As the power returns to the device, you should see several green lights. It is normal for one or more lights to blink temporarily while the device comes back online. If the STATUS, POWER or VOICE lights remain unlit, or if they turn a solid amber or red color after the reboot, please contact your carrier provider for further diagnosis.

Troubleshooting No Dial Tone on Copper

Make a test call to the line that does not have dial tone. If you get an immediate busy signal, this could indicate an issue on the physical line itself; in which case the carrier will need to be engaged to dispatch for repair. If the line rings on the caller’s side, but not at the receiving end, it could indicate an issue with a phone system. However, it could also be an issue on the physical copper itself. The carrier will need to run further tests.

Note: You can also check for dial tone at the demarc (demarcation point) by plugging a set in directly; however, we recommend this only for licensed electricians

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