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[aprssig] AX25 Protocol group (Jack Chomley

Stephen H. Smith wa8lmf2 at aol.com
Mon Jun 2 21:02:10 UTC 2008

Phillip wrote:
> From what I can gather from his message is, that this appears to be a 
> for gone conclusion
> and that these changes are going to happen some time .
> This will impact on every application that uses the ax25 protocol  if 
> I am not
> mistaken.
> Does this impact on the APRS spec and those that produce
> firmware for trackers etc.


> Remembering that there are over 5000 Kenwood D7 series
> aprs capable radios that probably can't be upgraded
> UI-View will not be able to be upgraded
> Every TNC will need to be upgraded .

The problem is that most TNCs CAN"T be upgraded.  

All the "classic" TNCs   (AEA, TNC2,  Pre-KPC3+ Kantronics) etc,  that 
comprise  probably the majority of the APRS digipeater/igate 
infrastructure,  are essentially orphaned products from the heyday of 
packet over 20 years ago.  

The TNCs still in current production ( TNC-X, TinyTrack4, Tracker 2, AGW 
uTNC, etc.) have the potential to be upgraded since they are in current 
production.    I suspect UI-Digi for the TNC2 may now be an orphan with 
no further development of the closed source code likely.

I am not sure of the implication for KISS-based TNC modes.  Since the 
KISS mode moves all the construction of the packets and their headers 
out of the TNC and into the software on the computer, it may be still be 
possible to use "classic" TNCs in KISS mode if the supporting software 
is updated.     You just wouldn't be able to run them in non-KISS mode; 
i.e. as stand-alone digipeaters. 

Since many TNCs in KISS mode are operated that way by the AGW Packet 
Engine, updating this application would be absolutely essential.  

This would probably be the final death blow to DOS APRS since the 
program only works with classic full-function TNCs.  It won't work with 
the modern TNCs that are KISS-only devices.  [Unless of course, you want 
to spring for a $300 KPC3+,  assuming Kantronics decides it's worthwhile 
to develop yet another firmware revision (V 10.0 ??) for the KPC3+).  

This whole mess sounds similar to the network armageddon looming in the 
Internet IP V4 to IP V6 changeover that will be forced on us by the 
exhaustion of current IP addresses.   [That will obsolete a vast 
proportion of the current Internet-using software and hardware.]

Or the chaos just now beginning to unfold in the mandatory 
analog-to-digital TV switchover in the U.S.     [The much-vaunted 
government-subsidized digital-to-analog converter boxes aren't receiving 
all the channels users got formerly in the analog mode. I.e. formerly 
noisy but still usable analog channels  are falling below the digital 
error-correction threshold in digital mode and aren't being received at 
all -- the usual all-or-nothing  perfect-picture-or-black-screen nature 
of digital.]


Stephen H. Smith    wa8lmf (at) aol.com
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