How to Send a Fax with VOIP

Sending a fax with VoIP (Voice over Internet Protocol) can be a convenient and efficient way to transmit documents. ​Many businesses and individuals use VOIP for common phone calls on a regular basis, but is it reliable for sending and receiving fax?  Let's take a look in this article.

What is VOIP?

VoIP, or Voice over Internet Protocol, is a technology that enables voice communication over the internet instead of traditional phone lines. With VoIP, analog voice signals are converted into digital packets and transmitted over the internet to the recipient. This technology has revolutionized communication, allowing for cost-efficient and flexible phone systems.

Can I Transmit Fax Documents Over VOIP?

​Yes, it is possible to transmit fax documents over Voice over Internet Protocol (VoIP) networks, but there are some considerations and potential challenges to keep in mind. Fax over VoIP can work, but it may not be as reliable as traditional analog faxing. Here's what you need to know:

  1. VoIP Limitations: VoIP was primarily designed for voice communication and data transmission, not for faxing. The nature of VoIP can introduce packet loss, jitter, and latency, which can negatively impact fax transmission.
  2. T.38 Protocol: To facilitate fax transmission over VoIP, the T.38 protocol is often used. T.38 is designed to convert fax signals into data packets that can be transmitted over IP networks. Many VoIP service providers support T.38, so it's important to ensure that your VoIP system supports this protocol.
  3. VoIP Quality: The quality of your VoIP service can significantly affect the success of fax transmission. You may need a VoIP service with high call quality and a stable internet connection to improve the chances of successful faxing.
  4. Fax Machine Compatibility: The success of faxing over VoIP can also depend on the type of fax machine you're using. Older fax machines may not work well with VoIP, while newer models designed for VoIP may have better compatibility.
  5. Configuration: Proper configuration of your VoIP equipment and network is crucial. This may involve adjusting settings in your VoIP adapter or router to prioritize fax traffic or improve the quality of the fax transmission.
  6. Testing: Before relying on fax over VoIP for important documents, it's a good idea to conduct testing to ensure that it works reliably. This can help you identify and resolve any issues before relying on it for critical communications.

Does It Give Good Results?

Well, that's another matter entirely.  From our tests, faxing with VOIP ,besides being more complicated doesn't work consistently.  Sometimes you can fax a page, but then it cans top working, sending data that isn't normally supposed to travel over IP. This makes VOIP faxing unreliable, and that's why FOIP or Fax Over Internet Protocol was developed.

The Better Alternative: Fax over IP

What Is Fax Over IP

Fax over IP, or FoIP, is a solution that allows users to send and receive faxes using their VoIP system. Instead of relying on a physical fax machine and an analog phone line, FoIP utilizes a digital transmission method. The fax document is converted into digital data and sent over the VoIP network. This eliminates the need for a dedicated fax line and streamlines the faxing process.

The best way for your business to get access to FOIP technology is to use an online fax service. These services act as a bridge between your computer and the recipient's fax machine. You simply upload your document to the online fax service, enter the recipient's fax number, and the service will convert and transmit the fax using its own infrastructure. This method is particularly useful if you don't have a physical fax machine or prefer a more streamlined approach.

With an online fax service, you typically send fax from Gmail or other email address you have, but they also give you other options, such as faxing from the service's main page or through a mobile fax app.

Porting Your VOIP Number to an Online Fax Services

If you already have a VoIP number that you would like to use for sending and receiving faxes, you can easily port it to an online fax service. This allows you to keep your existing number while taking advantage of the features and convenience offered by an online fax service. It typically involves contacting the VoIP provider and requesting the porting of your number to the chosen online fax service. This makes it possible to fax with your Google Voice VOIP number for example.

The fax number porting process may take a few days to complete, but during this time you'll be given a temporary fax number.


Sending and receiving faxes with VoIP can be achieved but it offers dubious results, if any. Fax over IP (FoIP) eliminates the need for a physical fax machine and analog phone lines by using digital transmissions. Another option is to use an online fax service that acts as an intermediary between your VoIP system and the recipient's fax machine. These services allow for seamless faxing without the hassle of compatibility issues. If you already have a VoIP number, you can port it to an online fax service and enjoy the benefits of both systems.