How Does a Fax Work?

Fax A Beer?

Hank Williams, Jr. once wrote a song called "Fax Me a Beer." It would be pretty amazing to fax a drink over a telephone line. But when you look at the technology and process of faxing information it can also seem pretty impressive. Facsimile machines, or fax machines as they are more commonly known, made their way to the public sector in the 1980s. The machines were a great way to send information from one office to another without having to send documents through regular mail. By faxing information on inexpensive equipment, an office could not only save money from postage but days of time.

The Fax Process

Fax machines work by sending the information over a phone line. Basic fax machines consist of a phone jack, loading tray, scanning component, coder/decoder and output tray. A document is placed into the loading tray. The machine accepts the document and rolls it on a rotating drum. As the paper passes over the drum, the fax machine takes a picture of everything written on the document. It then passes the information onto the encoding component.

The encoder would take that information and compress it into a smaller code to transmit over the phone line by assigning codes that represent either a black dot or a white dot. Once the document is scanned, the fax machine pushes the paper to the output tray. The sender dials the phone number of the receiving machine. After a series of rings, he hears a very high-pitched sound that signals the receiving machine is ready for the information. The outputting machine would then send the compressed information over the telephone line to the receiving machine. For the receiving fax machine, the end user must make sure that there is paper loaded in the tray so that it can begin to print out the telephoned information. The fax will start to decode the black-and-white dots into the actual original image. Once that is done, the fax machine hangs up.

Modern Advances

Older fax machines used thermal paper and black ink to print out received faxes. More modern machines use inkjet and laser printing technology, making the process faster and the machines much smaller. Many copy machines now have fax capabilities because of these technological advances. Fax machines can even fax their information to a computer account instead of another fax machine. Who knows? In the near future we may be able to fax that beer after all.