Comcast uses a telephone modem device called an embedded Multimedia Terminal Adapter, or eMTA, as part of the telephone service it provides over cable lines. Problems with the phone service can include no dial tone and other issues. You can accomplish some diagnostics by identifying lights on the front of the modem and you can often fix the telephone modem by resetting. Slow Internet service when browsing for example, can be fixed by resetting the cable modem.
Check that the "Power" light is on if you are having problems with telephone service. The "Power" light is the right-most light on the front of the eMTA. Plug the eMTA into a working power outlet if the light is off. The "Online" light is the fourth light from the right. It should be solid. Push the white "Standby" button if the "Online" light isn't solid.
Check the "Telephone 1" or "Telephone 2" lights are solid. If either are flashing, identify off-hook handsets, and place them back on the hook.
Reset the cable modem and eMTA if you continue to experience poor phone service, or slow Internet. Press and hold the "Reset" button on the cable modem -- which is distinct from the eMTA. If the cable modem doesn't have a "Reset" button, shut off your computer and unplug the cable modem from the power at the wall. Wait a few seconds and plug it the cable modem in again. Allow half-a-minute and restart the computer. Try the services again.
Reset the eMTA if phone service is still poor. Insert the tip of a ballpoint pen into the "Reset" hole on the back of the eMTA until the lights go off. Wait for the device to power back up and try the call again.
- Contact Comcast's customer service if the "Telephone 1" or "Telephone 2" lights flash slowly on the eMTA telephone modem.
- Photos.com/Photos.com/Getty Images