I would look at the directory entry for /dev/ttyS0 and be sure its
permissions are OK. You probably should be doing this as root. Another
thing to check is to see that the port is not locked. Also, be aware
that the port that corresponds to DOS com1 is also known as /dev/cua0,
and could also be linked to such names as /dev/modem or /dev/tnc. If a
lock exists under another device name it will be ignored, but if another
active program is using the port you'll have troubles.
All this is speculation, I haven't seen the actual messages you report,
or at least I don't remember them. I had a flurry of problems when started
using Linux ax25 just a few weeks ago, eventually all got straightened
out.
It is helpful to be able to go back to MS-DOS easily and use a terminal
program or JNOS to verify the TNC is in the state you expect. I found
it particularly easy to to get the TNC into a state that was neither
KISS mode nor standard TNC interface, and I couldn't figure out how
to use Minicom to get it back into KISS, nor were my attempts to send
strings to the TNC using simple C programs successful. The best thing
for me was to run Pacterm or Procomm under DOS, do the "intface kiss"
and "reset", and then restart Linux.
Good luck,
Al
--------------------------------------------------------
Albert S. Woodhull
tyhxm.riac@mx.dy.fi
otq.xnltxyr@dadeschools.net
terhi.victor@logonet.com (solamente dentro de la UNAN)
wrems@csc.fi