control-S

( vi.)

   "Stop  talking  for  a  second." From the ASCII DC3 or XOFF character
   (the  pronunciation /X-of/ is therefore also used). Control-S differs
   from {control-O} in that the person is asked to stop talking (perhaps
   because  you  are  on the phone) but will be allowed to continue when
   you're  ready  to listen to him -- as opposed to control-O, which has
   more of the meaning of "Shut up." Considered silly.

[glossary]
[Reference(s) to this entry by made by: {control-O}{control-Q}{XOFF}]