A TTY may refer to any of the following:
1. Short for teletypewriter or teletype, TTY is an electronic typewriter or teleprinter with a keyboard and printer. Each time a key is pressed, it would be printed to paper like a typewriter. Later, modern TTY machines also print to a screen. Teleprinters were widely used in the late 1800s and early 1900s. Today, they are replaced by computers with keyboards.
Teletype machines were available in three different modes shown below.
- ASR (automatic send and receive) — Able to send and receive.
- RO (receive only) — only capable of receiving data and not sending.
- KSR (keyboard send and receive) — TTY with keyboard capable of sending and receiving data.
2. Today, TTY describes a terminal session (virtual terminal) or line. Linux users may view a process or which users are logged in by typing a tty, such as ttyx, where x is any numerical value. For example, tty1, tty2, tty3, tty4, tty5, and tty6.
With recent versions of Linux, the GUI (graphical user interface) is loaded as the first virtual terminal instead of the seventh one. If you're accessing the terminal from a GUI, use Alt+← and Alt+→ to navigate between all virtual terminals.