(FACSimile) Originally called "telecopying," it is the communication of a printed page between remote locations. Fax machines scan a paper form and transmit a coded image over the telephone system. The receiving machine prints a copy (a facsimile) of the original. A fax machine is made up of a scanner, printer and modem with fax signaling.

Group 1, 2, 3 and 4
Fax standards were developed starting in 1968 and are classified by Groups. Groups 1 and 2, used until the late 1980s, transmitted a page in six and three minutes respectively. Group 3 transmits at less than one minute per page and uses data compression at 9,600 bps. The Group 3 speed increase led to the extraordinary rise in usage in the late 1980s. Group 3 resolutions are 203x98 dpi in standard mode, 203x196 in fine mode and 203x392 in super fine mode.