suspend-tty

suspend-tty is a built-in function in `C source code'.

(suspend-tty &optional TTY)

Suspend the terminal device TTY.

The device is restored to its default state, and Emacs ceases all
access to the tty device. Frames that use the device are not deleted,
but input is not read from them and if they change, their display is
not updated.

TTY may be a terminal object, a frame, or nil for the terminal device
of the currently selected frame.

This function runs `suspend-tty-functions' after suspending the
device. The functions are run with one arg, the id of the suspended
terminal device.

`suspend-tty' does nothing if it is called on a device that is already
suspended.

A suspended tty may be resumed by calling `resume-tty' on it.