Source : Free On-Line Dictionary of Computing

remote echo
     
         (Obsolete: "full-duplex") A mode of operation
        of communicating programs or devices in which the sending
        system does not display the characters the user enters, but
        only sends them to the remote system which then "echoes" them
        back to be displayed to the user.  This lets the operator see
        not only typing errors, but also transmission errors.  This is
        now the usual mode of most systems with remote users.
     
        Contrast: {local echo}.
     
        (2000-03-30)