A TTY (teletypewriter) is an input device that allows alphanumeric characters to be typed in and sent, usually one at a time as they are typed, to a computer or a printer. The Teletype Corporation developed the teletypewriter, which was an early interface to computers. Teletype mode is the capability of a keyboard, computer, application, printer, display, or modem to handle teletypewriter input and output. Basically, this is a one-character-at-a-time mode of sending, receiving, or handling data, although it is often modified to handle a line of characters at a time. Since this mode requires little programming logic, it is often used where memory is limited. The Basic Input/Output Operating System (BIOS) sends messages to a PC display using teletype mode. Most printers offer a teletype mode. The simplest video display output format is text in teletype mode. Many modems today continue to include support for a TTY interface.

Selected Links

TTY Devices and Serial Communications describes how to manage TTY devices for an AIX operating system at the University of Texas in Austin.

TTY Interface is a shareware program designed for handling TTY messages received in submarine rooms in ATA-2 (Baudot) into ATA-5 (ASCII).

The Virginia Department of the Deaf and Hard of Hearing provides information about their TTY Text Telephone program.