VoIP and Fax - An Introduction

Traditional fax machines have always posed a bit of a problem for VoIP networks. This is because VoIP technology encodes analog sound in a specific manner for transmission. Fax on the other hand requires another method of encoding which doesn't work seamlessly with existing VoIP equipment. There are many ways of getting over this limitation and we take a look at some of them as well as fundamental changes in the fax industry.

Connecting Regular Fax machines to VoIP

A new standard has been developed for encoding fax signals called T.38. Devices which implement this protocol allow a fax to be sent over the VoIP network without any problem. Now either a fax machine itself can be Internet aware - also called IAF or "Internet Aware Fax" - or a device can be attached that converts the analog signals from a regular fax machine into the format required by T.38. But even this isn't enough by itself. To handle the fax signals properly, even the VoIP gateway has to be T.38 enabled. Once this happens, the signal can be properly handed over to the Internet.

With these modifications, it might be as simple as just plugging a fax machine into a VoIP adapter instead of a phone jack to get fax seamlessly working.

Changes in the fax industry

But changes in the fax industry itself are threatening to do away with legacy fax systems. Unlike voice, fax doesn't require real time infrastructure and so functions more like email. Many people fax printed documents which are then converted to analog signals for transmission. Instead, it's much easier to send the document itself as an email.

There are situations however, when signed documents for example need to be sent and it's here that regular fax machines provide a service. The cheap and easy way of scanning a document and sending it makes it very hard to replace.

Another way in which the Internet has transformed fax is by the use of Fax servers. These accept a fax message from a regular fax machine over good old PSTN. However, instead of sending it to another machine, the server makes provisions for the receiver to get it by email instead. This ensures that no one else can read the fax and saves the receiver the trouble of digitizing it once again if necessary.

It'll take a few more years for the Internet fax industry to stabilize. But even now, organizations are able to do away with a lot of wastage and outdated infrastructure by making use of fax with VoIP.

Bhagwad is an expert in Hosted Phone Services. He also specializes in Hosted PBX provider selection.