Source : Free On-Line Dictionary of Computing

talk mode
     
         Using a {talk} system.  E.g., "{B1FF} had me in talk
        mode for hours last night.  I had to bring his box down just
        to get him to shut up."
     
        The (1980s?) term now is as dated as talk itself which has
        been largely replaced by {chat}.
     
        [{Jargon File}]
     
        (1998-01-19)