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Troubleshooting Your XFINITY Voice and Fax Machines

Find troubleshooting tips about using fax machines with XFINITY Voice service.

Account Configuration

Dedicated Fax Machines (Always On)

If you would like to have a dedicated fax machine that's always on as well as voicemail, you must have a second telephone line for the fax machine. Without a second line of service, you may not receive a fax, and callers may not be forwarded to voicemail.

Note: If you only want to plug in your fax machine periodically, a second line is not necessary.

Incompatible Equipment

For a list of devices with known XFINITY Voice-compatibility issues, including fax machines, see Equipment Incompatible with XFINITY Voice.


  • Always dial 1 before the area code prefix.
  • Verify that the number is dialed correctly.
Note: Many fax machines cannot differentiate between long distance and local calls, so adding a 1 ensures a proper connection to the number dialed. Permissive dialing, or skipping the area code and only dialing a seven-digit telephone number, is not available in all areas.

Recommended Settings

  1. Ensure that there are no ring types selected on your phone.
  2. Check the ring pattern in your fax setup. It should be set to a basic or standard ring cycle.
    • Note: If you have a custom or distinctive ring (also known as a teen line) for the fax machine, the setting needs to be reset from custom ring to standard (or basic ring).
  3. Check the auto answer or manual answer setting.
  4. Set the fax machine to its lowest baud rate setting - usually 9600. This may also be labeled as transmission speed or something similar, depending on the manufacturer.
  5. Set the error correction mode to off or its lowest setting.
    • Note: This can improve the ability of the fax machine to successfully send a fax. However, the received fax image quality might be affected. The Error Correction Mode is typically found in the Advanced menu.
  6. Change the Fax Speed Adjustment setting to Medium to improve the ability to send a fax over an IP network.
    • Note: Not all Hewlett Packard (HP) fax products include the Fax Speed Adjustment setting.
Note: A fax machine can sometimes detect if another machine is not color-capable and offers the option to send the fax as black and white. However, this might not always be the case, so try to avoid sending color faxes, unless you are sure that the other fax machine is capable of receiving them.


Standard Wired Hookup

If you have only one line that you leave connected to your fax machine for occasional use, check how the telephone cable is connected. The fax machine must be connected directly to the wall phone jack, and the cable should be plugged into the jack on the fax that is labeled Line, 1 – Line, To Wall Jack or has an image of a wall jack.

If you have a second line that is dedicated to faxes, the fax machine should be plugged directly into the Telco 2 port of the embedded multi-terminal adapter (eMTA). This provides constant fax service and does not require any additional charges or labor to set up phone jacks for the second line.

Silver Satin Two-Pin Cable

If you have an HP fax machine, use the phone cable or connector provided with the machine. These models come with their own phone cable or converter because HP uses two-prong conductors instead of the standard four-prong conductors.
A comparison of a 2 Prong Connector and a 4 Prong Connector.

Two-Pin Silver Satin Jumper

All fax machines are sensitive to supervisory voltage on the two outside pins of a four-pin Silver Satin Jumper, so always use a two-pin Silver Satin Jumper on fax machines to eliminate this possibility.

In addition, all fax machines come with a two-pair Silver Satin Jumper (Red/Green), which is what the installer should use.

Some fax machines, especially HP models, are polarity-sensitive. HP fax machines don’t support any activity on the line 2 pair of Silver Satin, which is why they ship with a silver satin line that only has one line (Red/Green). Please ensure that line 2 (Yellow/Black) is not connected to the fax machine.


Most fax machines require correct polarity, which is mainly the case for receiving faxes. This depends on make and model; however, the fax may only be looking for the ringing voltage on the ring line, not the tip. If polarity is reversed, it will not recognize the phone is ringing.

Some machines also don’t like to communicate on reversed lines. This is common with HP fax machines.

Once Correct Wiring is Confirmed

  1. Powercycle the fax machine, and try again by dialing 1 before the area code.
  2. If this does not work, connect the fax machine directly to the eMTA and try again.
  3. If you continue to experience issues, please connect a telephone to the outlet to see if there’s dial tone and a call can be made.

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