Fixing no dial tone on VoIP.

Use these step by step instructions to re-establish lost dial tone your VoIP service.  Loss of dial tone on your VoIP phone can be corrected in a systematic process of first checking your Internet connection, then each piece of equipment back to the phone itself.  In some cases there could be a router between the modem and in some cases there might not be.  A valid LAN IP address and access out to the Internet from the ATA is what you want to verify.

Step 1 check your Internet connectivity.

Starting with your modem, either DSL or cable make sure that your Internet connection is up.  This can be done by using a PC and surfing a website. 

If you cannot surf:

• Check your modem's lights and if it is synced up power cycle the next device that is connected to it.  This would usually be a router or a router/ATA.  After power cycling the router device, if an ATA or IP phone is plugged into the router power cycle the ATA or IP phone.  Give it time to re-register and then check again for dial tone.  Check again for PC Internet connectivity.  If the PC has Internet access and not the IP endpoint (no dial tone), check that it is getting handed an IP address. [Checking a sipura for an IP address.]
• Make sure the ATA has a power light.
• If the ATA has an IP address and will not register to dial tone change the Ethernet cable and port on the router and retry.  If that fails call your VoIP provider and ask them what they see at their end.

If you can surf:

• Power cycle the ATA, ATA/router or IP phone.
• Make certain that the phone is not the issue.  Plug an analog corded phone directly into the ATA without any other splitters, etc.  Make sure the phone is in line 1 (Usually where dial tone would be found on a single line account.) If dial tone, go to step 2.  Otherwise change phones and the phone line, as a test.
• If the ATA/router is plugged into another router move it to the first position after the modem.  Power cycle and check for registration and dial tone.
• If there are multiple ATAs connected to a router, disconnect all of them and then reconnect one at a time, checking for dial tone before connecting the next one.

Step 2 check for a device off-hook.

Having established dial tone after connecting one phone directly  into the ATA or ATA router, next you must look for an issue with a device (phone, fax, alarm, etc.) off-hook.  An off-hook phone or fax keep the line open.

• After connecting the phone line from the ATA to back to a wall jack, and no dial tone, one by one check all phones and other devices to make sure that none are not keeping the line open.  If need be disconnect all phones, establish dial tone on one phone, then reconnect each phone/device until the problem is isolated. 
• On problem device, check for splitters that could be causing the issue.
• Be aware that some alarms can cause these issues and may release the line only to have the issue again at a later time.