Fax Machine

Long before the Internet completely revolutionized businesses, fax machines made transporting documents as easy as picking up the telephone.

How it Works

Telephone
Modem
Computers

Before the rapid adoption of the Internet, the only way to transmit documents immediately was to use a facsimile, or fax, machine. Letters, notes, even photographs, can be fed through the machine, transmitted over the phone line using a modem, and be reproduced on the other end in less than a minute. The fax machine contains parts that are similar to those found on full featured computer systems, such as a scanner, printer, and modem. Faxes are most often used in businesses, and usually have their own phone number. Publicly accessible fax machines are available in full service copy shops, hotels, and airports, usually costing a few dollars per document.

How it Works
Fax machines act just like telephones, except they use modems to transmit binary data instead of voices. When you dial the phone number of another machine, they both make squeaky modem noises. These sounds indicate the modems are adjusting themselves to operate co-operatively. They both have to run at the same speed, and be able to interpret the information in the same way. Once connected, your document is fed through a scanner. One part at a time, a bright light illuminates the document, and the image on the page is reflected by mirrors onto photo-detectors, light sensitive devices that can tell where information is and where blank white space is. This information is converted into digital (binary) data, and streamed through the modem, over the phone line, and into the other fax machine’s modem, where the information is interpreted and reproduced using a printer. Most fax modems operate at 9 200 bps or 14 400 bps, significantly slower than those used by computers to connect to the Internet. (Many computer modems support faxes; software programs are available that allow you to send and receive computer-based faxes directly from your screen, so you’ll never even have to bother with paper based documents). Sophisticated fax machines can send the same document to dozens, even hundreds, of fax machines at one time. While most businesses have made much of their document work computerized, faxes are still easier to send paper based documents in a flash.

Sources
Click here for a list of sources used in this project.
Glossary
All the words in bold are found in the Glossary. If you don't understand a word, click on the beside it, to go directly to the Glossary Page.
[/10005/library/fax.html]
Unless otherwise stated, information on this site was created by The Unica Island Team, and may be reproduced for educational purposes without permission. For complete information, please see the copyright information pages.