Fax modems are a special kind of modem that allow you to send faxes. They differ from regular modems only in that the data they send is designed to be interpreted and presented by a fax machine or by another fax modem.
Modem Basics
The word modem stands for “modulator-demodulator.” A carrier signal is modulated (modified) to create tones that a computer can understand. The sounds then are demodulated, or interpreted, at the receiving end.
Fax Basics
Fax is short for facsimile, which literally means “copy.” An image is translated into a format that can readily be transmitted over a telephone line.
Fax Modems
Fax modems bring together faxes and computers. Fax modems usually are installed as a motherboard or laptop card, but also can be external, connected to a USB or parallel port. Each modem interfaces to your phone line via a standard telephone jack.
Sending
Using fax modem software, the sender selects a document from her hard drive. She enters the telephone number of the receiving fax and hits send. The document is modulated for transmission by the modem and sent over a phone line to the receiving fax machine or fax modem.
Advantages
Fax modems offer a less bulky, cheaper alternative to faxing than an actual fax machine. Although faxing has to some extent been replaced by email, it is useful to have fax capability when sending sensitive documents.