GOfax.IP - T.38: Fax over IP

Fax technology may appear to be somewhat antiquated in the age of email and the Internet, but it is still being used in daily business. For this reason, integrating email and fax has long been a topic. This is now being addressed by various open-source projects, with the well-known HylaFAX project at the forefront. A complete eco system has developed around HylaFAX and similar projects to address a wide variety of business requirements related to use of fax and email. For example, with the GOfax project GONICUS has created a solution that combines IT systems with email and fax technology in a manner that is convenient and easy to manage.

However, the growing prevalence of Voice over IP and associated protocols has also resulted in changes and challenges for such setups. The T.38 protocol is today being used for transmitting faxes via IP networks. Unfortunately the use of T.38 is not directly supported by HylaFAX.

We have now initiated an open-source project that forms the link between the T.38 protocol (Fax over IP) and HylaFAX. Based on various other open-source software components, GOfax.IP offers the fascinating option of integrating Fax over IP into existing fax server infrastructures. This results in the following benefits, among others:

  • Virtualisation of fax servers
  • Economic viability — T.38 media gateways are often more cost-effective than ISDN server cards where large numbers of channels are used
  • Seamless integration through open standards
  • Support for both T.38 and analog fax via G.711

What does a typical setup look like and how does GOfax.IP work?

In a modern Voice over IP infrastructure, either media gateways (for classic PSTN) or session border controllers (for SIP trunk connection) are frequently used at a public network interface. In both variants, IP is then used to transmit voice and data across the local network. A similar principle applies for fax transmission. In this instance, the T.38 protocol is used to realise Fax over IP. The endpoint in the local network must then be able to process the T.38 protocol. This is where GOfax.IP comes in: it can be used to add T.38 capability to existing HylaFAX setups.

The basis of GOfax.IP is a significantly streamlined FreeSWITCH installation, which processes the SIP protocol and receives IP faxes. Data is prepared and then forwarded to HylaFAX in the appropriate format. In this way, existing HylaFAX installations, including all associated and established components, can continue to be used without making any changes. An existing GOfax installation can, for example, also have support for T.38 faxes added. Using IP for the transmission between the gateway and fax server also opens up opportunities that are more difficult when using a local ISDN card (virtualisation, high availability).

GOfax.IP is the missing link between modern Voice over IP infrastructures and classic, tried-and-tested fax server installations.

GOfax.IP is available at Github for download and contribution .