a telegraphic apparatus by which signals are sent by striking the letters and symbols of the keyboard of an instrument resembling a typewriter and are received by a similar instrument that automatically prints them in type corresponding to the keys struck.
hardware (Nearly always abbreviated to "teletype" or "tty") An obsolete kind of terminal, with a noisy mechanical printer for output, a very limited character set, and poor print quality. See also bit-paired keyboard. (2000-04-02)