

Whatever you type on one typewriter gets automatically printed out on the other. To understand the basic principle behind teleprinters, imagine two electric typewriters linked together by wires (or a wireless radio link). An excerpt from a 1929 Teletype advertisement. Teletype Corporation’s products became so ubiquitous that “teletype” evolved into a generic term synonymous with “teleprinter,” especially in the field of computers. The term “teletype” originated as a trademarked term for a brand of teleprinters created by the Teletype Corporation in 1928.

A teletype (or more precisely, a teleprinter) is a communications device that allows operators to send and receive text-based messages using a typewriter-style keyboard and printed paper output.
