set-output-flow-control

set-output-flow-control is a built-in function in `C source code'.

(set-output-flow-control FLOW &optional TERMINAL)

Enable or disable ^S/^Q flow control for output to TERMINAL.
If FLOW is non-nil, flow control is enabled and you cannot use C-s or
C-q in key sequences.

This setting only has an effect on tty terminals and only when
Emacs reads input in CBREAK mode; see `set-input-interrupt-mode'.

See also `current-input-mode'.