What is Fax over IP (FoIP)?

Do you have SIP trunking customers that are still addicted to old technology (think fax or dial-up internet). It’s time to encourage them to look into Fax over Internet Protocol (FoIP). They’ll still be able to fax documents to clients or colleagues, but they avoid long-distance phone lines and other issues associated with traditional faxing. While new technology can initially scare some customers off, explaining what it is and how it works will help overcome some of their objections. Here’s how you can teach your customers exactly what Fax over IP is:

What it is

FoIP uses VoIP technology to send documents to traditional fax machines. Faxing can be done through special software downloaded to a computer, through a traditional fax machine that uses a gateway to connect phone lines and the internet, or through a FoIP-specific fax machine. Once the sender faxes the document, the recipient receives the fax in real-time on their fax machine or their computer if they use FoIP software.

How it works

Some customers may want a more in-depth explanation of exactly how FoIP works. While you probably like to geek out about this stuff like we do, to keep it simple, just explain that a traditional fax machine is analog–it sends information via a circuit. FoIP employs digital technology, converting the document into packets of information that travel in a continuous stream over the internet.


A common objection to FoIP is that it isn’t as reliable since it relies on a packet-switched network. In the past, documents sent with FoIP could potentially be corrupted or damaged or not received at all. If the network timing is off even just a little bit or if a packet is lost, the fax transmission can be less than successful.

These problems can be remedied, however, if your customer’s internet has plenty of bandwidth. FoIP also employs error-correction protocols to eliminate as much packet loss as possible. As FoIP technology continues to be developed, it will become more and more reliable and convenient for your customers.


Introducing your customers to FoIP will streamline their communication technology. Instead of using two systems–phone lines and the internet–to communicate with their customers, they’ll be able to use one network. FoIP will also help them avoid high long distance charges and keep their costs down. They’ll have the flexibility to fax from the device of their choosing.


How have you introduced your customers to FoIP? Got any tried-and-true methods? If so, please share!