Fax Machine Basics: How They Work and How to Use Them

This page explains the basics of fax machines, provides instructions on how to use one, and includes links to fax machine manufacturers. A fax machine is a device that scans a document and sends a copy of it to a distant location using the telephone network.

While fax machines face strong competition from the internet these days, they remain popular in some countries, such as Japan, even among households.

How to Use a Fax Machine

Fax machines use various modulation techniques to convert information into a format suitable for transmission over telephone lines. These techniques are based on different V standards, such as V.27, V.29, V.17, V.34, and V.34bis. Let’s walk through the steps of how a fax machine works:

As shown in the figure, at the sending end, paper is fed into the fax machine.

1. The fax number of the receiving fax machine is entered into the sending fax machine.
2. After a handshake is established between the machines, the transmission process begins.
3. The sending fax machine, which contains a photosensor, converts the information (images/text) into a format suitable for transmission over the telephone line. In fax machines that use FSK modulation, an 800 Hz tone is used for white areas and a 1300 Hz tone is used for black areas.
4. This information is received by the fax machine on the other end, which then converts the modulated information and prints the information (images/text) back onto paper. This results in a copy of the original document being printed.

Fax Machine Specifications

Here are some common specifications to consider:

• Data compression format: JPEG, JBIG, MMR
• Fax resolution format: dpi (dots per inch) for black and white, color
• Internal Memory size
• Capability: ITU T.37 or any other supported standard