Like a cross between a phone and a printer, fax machines copy paperwork in a single location and print them out in one other — even hundreds of miles aside. Earlier than the ubiquity of computer systems and high-speed web and when the opposite choices had been snail mail or a courier, a fax may comparatively rapidly transmit medical information to docs, pictures to newspapers and invoices to purchasers. However how do fax machines work?
“Mainly, a fax machine scans a picture or a doc line by line, then transmits that scan to a receiver the place it is printed out and reproduced,” mentioned Jonathan Coopersmith, writer of “Faxed: The Rise and Fall of the Fax Machine” (Johns Hopkins College Press, 2015) and professor of historical past at Texas A&M College. Faxes function on phone strains right now, however early faxes (brief for facsimile machines) used telegraph strains, which transmitted textual content messages utilizing codes of lengthy and brief pulses, equivalent to Morse code. In actual fact, the fax was invented in 1843, three many years earlier than the phone. Faxes have stored the identical basic design and performance since that point, however the mechanics have modified, Coopersmith mentioned.
Within the 19th century, a fax machine’s stylus moved over a doc that was held in place. Every doc had a message that was written in ink coated with a handled dry resin generally known as shellac powder. “As your stylus goes, a lot of the line might be clean, however then it hits shellac, which raises the stylus and sends a beep to say there’s one thing right here, there’s black right here,” Coopersmith advised Dwell Science. At this time, faxes optically scan paperwork with out bodily touching them. These machines shine a lightweight, which displays off of the black (or printed) areas of the floor however not the white (or clean) areas.
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However how do faxes speak to one another? Earlier than sending a doc, the 2 faxes in numerous areas have a fast dialog, known as a handshake, to substantiate there’s actually a fax machine on the opposite finish, defined Abe Lopes, proprietor of Ace Copy Inc., an workplace gear restore store based mostly in Newark, New Jersey. “That is why you hear the little ‘deh-leh-lehhh’ sound, the little dial tones,” he advised Dwell Science.
Fax machines cut up a web page up right into a grid of many tiny squares, just like pixels. In actual time, the sending fax reads one line of squares at a time and makes use of beeps to inform the receiving fax whether or not the squares are black or white (represented by ones and zeroes, respectively), Lopes mentioned. “Because the paper is fed by way of the sending fax, the receiving fax is working concurrently,” he mentioned. “One fax is sending ones and zeroes, on and off indicators, whereas the opposite receives it, and interprets it again to black and white to print out.”
The important thing to a functioning fax is having two separate phone strains, Lopes mentioned. One line for the precise telephone and one other for the fax. “If the fax makes use of the identical line because the telephone and somebody picks up the telephone within the center, that may interrupt and knock off the transmission,” he mentioned. Which means paper jams, beginning over, or each.
Though fax machines could appear outdated right now in contrast with the comfort of attaching a PDF to an electronic mail or collaborating on a Google Doc, many medical workplaces and small companies nonetheless depend on faxes. And there is dwelling use, too. That is how Coopersmith grew to become fascinated with faxes. His mom in the USA loved utilizing one to speak with buddies in Russia and Thailand. “How neat,” he thought. “Here is a expertise so easy my mom can use it, but so sophisticated it will probably talk world wide.”
Initially printed on Dwell Science.