NAME
        Stop -- pause current activity on the parallel device

   FUNCTION
        This command halts the current I/O activity on the parallel
        device by discontinuing the handshaking sequence. The stop and
        start commands may not be nested.

   IO REQUEST
        io_Message      mn_ReplyPort initialized
        io_Device       set by opendevice
        io_Unit         set by opendevice
        io_Command      CMD_STOP (06)

   SEE ALSO
        parallel.device/cmd_start