How to fax with a FoIP fax machine

Last Update: August 9th, 2021

A FoIP fax machine (sometimes called a SIP fax) or fax machine that communicates over the internet (Fax over IP) work very much like a traditional fax machine. The only difference is that a FoIP fax machine can communicate with other FoIP fax machines over the internet, while a traditional fax machine can only communicate over a phone line.

What you’ll need

  • A FoIP capable fax machine
  • Another FoIP capable fax machine to send to
  • An internet connection
  • An ethernet cable to connect the fax machine to the internet (unless the fax machine can connect over WiFi)

Setup step 1 – Assemble the fax machine

Set up the fax machine as you would a regular fax machine.

The only difference with a FoIP enabled fax machine and a traditional fax machine is that there is no requirement of a phone line. Instead, an ethernet cable connects the fax machine to an internet port, or there is the capability of a WiFi connection.

Many FoIP enabled fax machines also have traditional phone line capability as well. These machines can send and receive faxes using either the phone line or their internet connection

Setup step 2 – Connect and configure the fax machine

First, follow the fax machine’s instructions to connect the fax machine to the internet using the internet cable or a WiFi connection.

Then, follow the instructions on how to configure the FoIP fax machine.

Some common methods of communicating are:

  • FoIP device only. This will only allow for faxing between FoIP enabled fax devices.
  • SIP. This will enable the fax to communicate with an SIP enabled phone number.
  • VoIP gateway. This will enable the fax to communicate over the internet to a regular phone number via a VoIP gateway.

Send a fax using the FoIP fax machine only

To send a fax from one FoIP device to another, you will need the IP address of the destination fax machine. You may also need a SIP username.

Typically the format of the fax will be the username @ the IP address. If the username is ‘9999’ and the IP address is ‘’ then a destination fax address would look like ‘[email protected]’.

Send a fax using a SIP server

To send a fax using a SIP server, you can use the destination phone number assigned to the SIP device.

Often there will need to be a username entered. If the username is ‘9999’ and the fax number is 12125551234 then the fax can be sent to ‘9999@12125551234’.

If using an SIP server and no direct access to the phone number, then faxes can only be sent to SIP enabled phone numbers.

Send a fax using a VoIP gateway

A VoIP gateway adds in the ability to communicate with the phone network. With a VoIP gateway in place, faxes can transmit with the FoIP device through the VoIP gateway to connect with any fax number.

Fax machines using a VoIP gateway can fax to either a SIP address or a regular phone number.