[FADCA] Interesting Note

[Chuck Hast]

We discovered that the Kenwood D-7 series embedded TNC will not pass
non-pid f0 packets at the hamfest the other day, we tried to use the D-7
which I have in my van as a digi to get to Tampa (we were able to hit
the tampa switch just fine from my van, so I set the portaswitch up to digi
via the van back to tampa, no joy. At first we thought it was a timing issue
because it kept on doing a rr on the frame previous to the level 3 frame,
but when I went to the van and started looking at the link from the vantage
point of the digi, I realized that the digi was not passing the pid 01 (ROSE
level 3 stuff) frames. I did not realize that digi's even looked at the PID in
a Ax25 frame as long as the frame was ax25. So if you are going to use
a Kenwood with the embedded radio as a digi to digipeat  level 3 stuff
don't waste your time.

That puts Kenwood even lower on my list of data radios, in truth the TNC's
for those radios were more designed for the APRS crowd than anything
else, they do APRs pretty well, but are a bit stupid when it comes to regular
packet.

Here is another bit of stupidity, the kenwood people in their infinite wisdom
have chosen to drop the ax25 ver 2, it is only running ver 1 in the TNC soooo...
If the far end sends a DISC frame your end will send a UA confirming the discon-
nect. BUT if the far end does not hear the UA come back it will send a
DISC again,
the disconnected TNC should send a DM saying I AM disconnected, shut up and
go away, but it does not, it sets there and sends NOTHING, so the far end sends
whatever it's retry count is of DISC frames until it times out. Don't
you just love
spectrum pollution like that? I will give them one good set of points
the 9k6 modem
and radio part work pretty well though the radio still needs about it seems like
100ms to get things in the right state in order to send or receive data.

Indeed it appears that connected mode was sort of a after thought, too
bad because
the radio is a pretty good box for packet. Sure wish there was a
simple way to put
in a different eprom, but I think it is all surface mount....


-- 
Chuck Hast 
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."