Type    Function        Comments
        0       Data frame      Rest  of frame is data to be sent on  the 
                                HDLC channel.

        1       TXDELAY         Second byte is transmitter keyup delay in 
                                10  ms  units.  Default value is 50  (500 
                                ms).

        2       P               Second   byte  of  frame  is  persistence 
                                parameter,  p: 0: p = (0+1)/256, 255: p = 
                                (255+1)/256 = 1.0. Default value is 64.

        3       SLOTTIME        Second byte of frame is slot interval  in 
                                10 ms units. Default is 10 (100 ms).

        4       TXtail          Second  byte of frame is time to hold  up 
                                the  TX after the FCS has been sent.  The 
                                bitstuffing  logic in the SCC delays  the 
                                datastream,  so  we need to wait for  the 
                                final  flag  to  really  leave  the  SCC. 
                                Parameter is set in 10ms units.  For 1200 
                                bps, this parameter should be at least 2. 
                                Default value is 3 (30 ms delay).

        5       Full duplex     If nonzero, TNC does not wait for receive 
                                channel to be silent before starting  TX. 
                                If  RX- and TX frequencies are different, 
                                full-duplex  us used.  Default is  0  (no 
                                full duplex).

        6       TNC special     Next byte controls special (TNC-specific) 
                                features  of the DTNC tnc,  like encoding 
                                control,  hdlc speed, etc. This parameter 
                                is TNC-specific, so MUST be changed if an 
                                other TNC is used.  See below.

        255     KISS exit       Upon reception of the FEND character, the 
                                TNC restarts (like a hardware reset)  and 
                                reinitializes.   Does  not  restart  KISS 
                                automatically.