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Fax Troubleshooting for Comcast Digital Voice

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Fax Troubleshooting for Comcast Digital Voice

Fax Troubleshooting for Comcast Digital Voice

Many of our customers take advantage of Comcast's competitive rates and add a second line just for their fax machines. Numerous makes and models of fax machines work with our Comcast Digital Voice service with no trouble at all. However, in rare circumstances, you may have problems getting your fax machine to work properly with our service. If that is the case, please contact Customer Service. We have trained technicians who can help answer your questions, 24 hours a day, 365 days a year.

  • You can call 1-800-COMCAST (1-800-266-2278).
  • You can contact E-Care here.
  • Or you can email us here. You should receive a response to your email in 24 hours or less, however for problems requiring immediate attention, please call or chat with us instead.

Here are a few steps you can try on your own.

  • Check to make sure that the fax machine is plugged securely into the wall power outlet and is turned on.
  • Depending on your setup, the fax machine may be connected to either a telephone jack in the wall or directly into the back of our telephone modem. Make sure that this line is connected securely at both ends.
  • Many fax machines have two jacks on the back of the unit: one to connect to the telephone jack on the wall outlet and another that can be connected to a telephone. Make sure that these cables are properly configured.
  • Check to make sure your Comcast Digital Voice service is working properly. You can do this by connecting a working corded telephone to the telephone jack you use for your fax machine. Try making and receiving calls on that telephone. If the telephone line does not work, please contact Comcast customer service for further assistance.
  • There is a limited number of devices that are more likely to not work with Comcast Digital Voice. You can see that list here.
  • Make sure you are using the phone cable that came with your fax machine. Some fax machines require special wiring or filters on the line. Contact your fax machine manufacturer for more details.
  • Try resetting your fax machine to factory defaults.
  • If you contact customer service, here is some of the information we may request from you:
    1. The make and model of your fax machine.
    2. Example telephone numbers of people who have issues sending or receiving faxes to or from you.

Message Edited by GeoffG on 08-23-2007 03:19 PM
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Regular Contributor

Re: Fax Troubleshooting for Comcast Digital Voice

Here are some more answers to questions on fax machines.

If you cannot receive faxes, check the following;

1) Is the fax configured to "auto received?" (Refer to your owner’s manual).

2) Is the ring cadence set for all ring tones? You want all ring types and you are not using a DSL connection. (Refer to your owner’s manual).

3) If manually receiving, are they using the correct command for this? (Refer to your owner’s manual).

4) Is the fax connected to a working jack for that line? To check this, take a known working corded phone and plug it into the telephone jack that you are using and check for dial tone.

5) If you have voicemail on the same line you have a choice:

have the fax set to answer under four rings

have the fax auto answer

get a 2nd line

remove voicemail.

If you cannot send faxes check the following;

1) Verify that the fax is connected to a working telephone jack (see #4 above).

2) Make sure that the dialing used is TONE, not pulse (refer to your owner’s manual).

3) If it is an HP fax, ensure you are using the silver/satin cord that came with the fax or the adaptor (refer to the manual).

4) If the fax has a speakerphone built in, what is the sound that you are hearing (fast busy, number cannot be completed as dialed, etc.)?

5) Verify that the number being dialed is correct.

6) Place a test call it to see if you can hear the fax tone. If you do not get the tone, it most likely on the receiving end.

7) If you have voicemail on the fax line, make sure you do not have any messages waiting, the stutter dial tone will cause some fax machines to think there is no dial tone.

8) Are you using a built-in speed dial? It may be dialing before you get dial tone and the first couple of digits may not be heard by the switch. Add 1 or 2 pauses in front of the number dialed (refer to your owner’s manual).


You have a few options to connect the fax to Comcast Digital Voice service;

1) Go direct from the back of the eMTA to the fax. Then, if the fax has a "tel out"

port, connect it to a normal telephone.

2) Use a splitter so you can have a telephone and a fax connected to the same line.

3) If connected to the inside wiring, use a wall telephone jack that has been activated for that line.

4) Going direct to the back of the eMTA, you can swap between your normal telephone and the fax.

In rare cases you may have call quality issues. This can interrupt the fax and in order to resolve, we will need to schedule a service call.

If these steps do not work please contact us.

Message Edited by JimWe on 05-09-2007 09:13 AM