Fax machines are some of the most common office equipment today. A fax machine, short for facsimile machine, basically sends and receives reproductions of a document through a telephone line. With a fax machine, sending documents to any point in the world has become fast, convenient and easy. Despite the presence of traditional courier services and the universality of email, the fax machine is still essential in any office for instantaneous sharing of documents such as proofs, contracts and other documents.

The fax machine's process is actually very simple. It is a scanner, a modem and a computer printer all in one device. First, as the sender feeds the paper document into the machine, a scanner or sensor translates the images into a sequence of light and dark dots. These dots are then encoded into audio tones and transmitted through a regular phone line. At the receiving end, the fax machine translates the tones and pieces the data together; then prints out a black and white reproduction of the original document sent.

Today, there are many types of fax machines available. Most are plain paper fax machines that use a typical copier, paper and inking process. These fax machines differ either by their sending speeds, printing technology and other features. Most fax machines send data at the top speed of 36.6 kbps or one page per 6 to 10 seconds.

Fax machine buyers can choose from a number of fax printing technologies including inkjet and laser fax. Inkjet fax machines turn out crisp and clear copies but are rather slow. Meanwhile, laser fax printers use the same technology as laser printers and can produce high quality copies rapidly. Also, today's fax machines have evolved into multifunction devices that incorporate the functions of scanners, copiers and computer printers.