control-Q vi. "Resume." From the ASCII DC1 or {XON} character (the pronunciation /X-on/ is therefore also used), used to undo a previous {control-S}.
control-Q DC1 XON <character> (Or XON, DC1, {Device Control} 1) The character with {ASCII} code 17, used in {software handshaking} to resume output after a previous {control-S}. [{Jargon File}] (1996-06-28)