This shows that the problem is in the connection between fldgi and the server.
The auto-restart monitor in pskmail_server looks at the ~/.fldigi/status_log.txt file.
The server sends a new mode to fldigi every minute, and this is recorded
in the status_log.txt file.
When nothing changes there for 3 minutes, fldigi is dead, or the link
between server and modem is broken, which will kill fldigi with 99% certainty.
That is when the auto-restarter kicks in, restarting the server/modem combination.
By looking into ~/.fldigi/status_log.txt you may be able to see the cause...
So it looks lioke a real problem, and most certainly the USB connection is the cause.
I run server 1.9.4 on 3 different servers (experimenting with server-to-server transfer),
and I see restarts about 1x per day on 1 of them (not on PI4TUE, with the IC7200).
The new server is on the download page at pskmail.org.
I changed to server 1.9.2 a while ago and didn't look at it for weeks.
Now I see, that it is restarting with "fldigi died..." all over again,
With the previous server version fldigi did not die for days, sometimes
Is there something I did not quite understand with version 1.9.2?
********************* Start of pskmail_server at Mon Oct 29 19:57:55 2012
Fldigi died, restarting at Mon Oct 29 20:08:15 2012 , $update = 304
Fldigi died, restarting at Mon Oct 29 20:08:29 2012 , $update = 318
Fldigi died, restarting at Mon Oct 29 20:08:43 2012 , $update = 332
Fldigi died, restarting at Mon Oct 29 20:14:27 2012 , $update = 309
Fldigi died, restarting at Mon Oct 29 20:14:41 2012 , $update = 323
Fldigi died, restarting at Mon Oct 29 20:20:15 2012 , $update = 310
Fldigi died, restarting at Mon Oct 29 20:20:29 2012 , $update = 324