How do Fax and VoIP Work Together?
Faxing in Today's World
There are many factors to consider before an organization implements VoIP to replace its legacy communication system: Internet connectivity, bandwidth, existing infrastructure, cost etc. Typically, managers review all the features they need from a business phone system and evaluate whether VoIP can provide them.
Fax capability is one such feature. It is easy to believe that nobody uses fax anymore but many business organizations continue to rely on fax machines either because their collaborators (suppliers, distributors, partners) still use it or it is required by federal regulations. This brings up the question: does fax work in VoIP environments?
Making Fax Work with VoIP
Unlike audio, fax data does not travel well over VoIP networks since it was developed for analog systems. The regular process of digitizing and compressing voice signals using codecs does not work well with fax. However, this does not mean that fax and VoIP cannot work together. Some small businesses prefer to connect their fax machines to an analog phone connection so that no changes are needed. Naturally, this solution will not work for larger organizations or those with high fax volumes.
Faxing over VoIP can be done in one of several ways:
1. Send faxes using the G.711 codec
2. Send computer faxes using the T37 protocol
3. Real-time fax using the T38 protocol
The first method is the simplest but is prone to errors. It may be enough for the occasional fax but no business can rely on it for long. The second method is very popular especially among companies that use hosted VoIP. It is often referred to as paperless faxing since the messages are usually delivered to an email inbox as attachments. Outgoing faxes can also be sent in a similar manner. The attachments can be printed as necessary. Some firms prefer to use IP fax machines which have the necessary algorithms to decode messages.
Using the T38 protocol provides the most consistent and reliable faxing experience. A T38 capable machine will convert the fax into an image which is sent to another T38 device where it is converted back into an analog fax. Businesses can even continue using their analog fax machines by connecting them to a T38 capable VoIP gateway. With this system, faxes are sent and received in real-time. For the end-user, the process appears the same as analog faxing.
The preferred fax method depends on the volume of faxes expected to be sent or received as well as the available infrastructure. Paperless faxes may be the best method for small and medium businesses while the T38 protocol is generally used by larger organizations.