How does a fax machine work?

In today’s business environment, the fax, or facsimile machine is an integral part of day-to-day operations and, in many instances, has replaced conventional mail as a means by which to convey information. Modern offices commonly send purchase orders, preliminary contracts, employment information, and other documentation in this fashion. Most of us are familiar with this technology but are unaware of the history of the fax machine and how it actually works.

It may surprise you to learn that the technology for the modern fax machine was actually developed in 1843 when a Scottish inventor, Alexander Bain filed a patent with the British patent office that essentially covered electronic printing. Bain invented the first fax transmitter, a clumsy scanning and recording device. His invention was followed in 1902 by a photoelectric fax system developed by Dr. Arthur Korn.

Further developments included AT&T;’s research and development into the conveyance of information via telephone lines in the 20s and the first machine that successfully sent photographs over the wires in 1924. The first documented radio fax was sent in March 1955. Photos were sent by “wire” for printing in newspapers all over the world.

By the middle of the 1980s, the office fax machine had become standard equipment, and, moving into the 21st century, this technology had also become commonplace in the home. Moving forward, advances have already been made in the area of integrating fax technology with the Internet and email.

The technology behind a fax machine is fairly simple. The machine itself is connected to standard phone lines. A document is inserted into the machine, where it is fed using a rotating cylinder. A light beam scans the document as it passes, and the light spaces in the document are translated into pulses of electric current by the photoelectric cell. Dark spaces in the document produce no pulses and grays are interpreted according to the intensity of the tonality.

The receiving fax machine picks up the transmission and translates the pulses into corresponding light and dark space on the paper. These pulses approximate the letters, drawings, photographs, diagrams, and white spaces on the original. Early fax machines required special paper, but technology has advanced to the point where today, standard copy paper can be used to receive faxes.

To send a fax, place the document into the feeder tray of the machine. Check the orientation of the document normally, the paper is fed face down. Once the paper is in the feeder, dial the phone number of the fax machine to which you are sending the document. You should hear a signal when the connection is made, although in many newer machines this signal is now silent.

Once the connection has been made, the document will be drawn into the machine and scanned by the photoelectric cell. When the transmission is complete, the line disconnects, and the document can be retrieved. Most fax machines provide some type of transmission confirmation, either as an individual notification or a log.

Technology in this area continues, and the latest development is fax that can be directed to an individual’s email address. Faxes can also be sent via email using integral scanners and special fax programs.

The software will compress the information in the fax and then digitize it for transmission to a standard fax machine, email account, or Internet account. With advances in cellular technology, don’t be surprised to find the receipt of faxes on cell phones or PDAs to be the next development.

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