November 7, 1988



               TNC-2 Software Release 1.1.6 Notes
               ----------------------------------


This  document  describes  the  differences  between  the  latest 
release  1.1.6 and the previous (1.1.5) release of TAPR  software 
for the TNC 2 Terminal Node Controller.

The reported checksum on powerup is $2E.

This release includes "KISS" capability from K3MC. 


                          NEW COMMANDS
                          ------------

KISS ON|OFF                                          default: OFF

This command is used to enter the "KISS" mode for operation  with 
various  experimental protocols.  KISS is used  with  intelligent 
host  computers.   The most popular use has been  in  conjunction 
with the KA9Q TCP/IP networking software, available from TAPR and 
elsewhere.

To  operate  KISS with this release, enter the command  KISS  ON, 
then the command RESTART (NOT RESET!).  The CON and STA LEDs will 
flash  three times when initially activated.  This  command  will 
then  have effect for subsequent power on/off cycles.  To  return 
to normal operation, enter the command PARAM <device> 255 at the 

      NET> 

prompt  if you are running the KA9Q TCP/IP software package.   If 
you  cannot send this parameter with the software you  intend  to 
use,  you  must  power the TNC off,  then  disconnect  the  bbRAM 
battery for several minutes, then reconnect the battery and power 
up again.

NOTE:     While  the  TNC  is  in the  "KISS"  mode,  normal  TNC 
          operation is suspended and the familiar command set  is 
          inoperative.

TXUIFRAM ON|OFF                                      default: OFF

This  command  determines  whether the  TNC  will  transmit  most 
unconnected information packets.

Setting  TXUIFRAMe  OFF  will  prevent  all  but  BEACON  and  ID 
unconnected ("UI") frames from being originated and  transmitted.  
This  is  most useful for BBS and other stations  which  tend  to 
leave  unacknowledged  data  in the TNC transmit  buffer  when  a 
connection is lost.  The normal behavior of a TNC would send  the 
buffered data as "UI" frames, adding to channel congestion.

The  behavior  with  TXUIframe  OFF  serves  to  reduce   channel 
congestion because the now useless data is never sent.

NOTE:     TXUIFRAM has NO effect on the digipeating of UI frames.  
          It  only  affects  frames  being  originated  at   this 
          station.



                             CHANGES
                             -------


o -  The  TNC  now requires that the Data  Carrier  Detect  (DCD) 
     signal  from  the  internal or external  modem  be  asserted 
     (true) for a packet to be received.  This change is intended 
     to  ensure  that a modem with a "threshold" control  is  set 
     properly.

     The  result  is that the station operator will set  the  DCD 
     control  in order to receive data.  This then  ensures  that 
     the TNC will have the best chance of detecting other station 
     activity,  reducing collisions that would  otherwise  result 
     from  jumping  on a channel believed to be open when  it  is 
     really in use by another station.

     This protection feature will be invisible to most operators.

NOTE:     To test with digital loopback, FULLDUP must be ON.  For 
          normal operation, FULLDUP should be set to OFF.

                 THE PACKET REVOLUTION REVOLVES!


                      Howard Goldstein N2WX
                      TNC-2 Software Design
                               'n
                         Damage Control