A fax is a system of data, written or graphic transmission over the telephone.
A very popular technological device in the last decades of the 20th century is called a fax or facsimile that allowed documents, texts and other data to be transmitted through a telephone line, generating a telecopy.
The fax works simply. It consists of three parts integrated and combined in a single device: a scanner, which is responsible for recording the data, texts and images present in the original document; a modem, which allows connection via telephone with another device with similar characteristics; and the printer, which when receiving a new document prints it quickly and economically on paper, producing a copy of the transmitted data.
The creation of the fax dates from the year 1851, shortly after the invention of the telegraph. The device was designed at the University of London, in a very rudimentary version. The first faxes could scan only in black and white, while over the years these systems became much more sophisticated, allowing the gray scale. Today faxes are multifunction devices that gather information in color, although gray is still being printed for an economical and speedy purpose.
Faxes were very popular devices in the middle of the 20th century, as a method of transmitting information at a distance quickly and accurately, before computers and other related devices reached the greatest popularity and expansion in the market. Many computers incorporated this functionality in the last decades of the century, through software that emulated the characteristics and operation of the fax.
Today this type of device is still used due to its reliability for certain types of information sending and receiving operations, although its use has been relegated to more or less exceptional circumstances.