Wvdial and mysterious /dev/ttyS0 permission change

[Alexander Fitterling <alexander.fitterling@gmx.net>]

Everyone.

Debian has some setting like this for my modem device

crw-rw----    1 root     dialout    4,  64  7. Jan 2002  /dev/ttyS0

I added all necessary users to group "dialout" at least to have them access 
our modem.

But when some users start wvdial and the line breaks if maximum idle time is 
reached wvdial still seems busy and still gets hold of /dev/ttyS0. After a 
user sends Ctrl+C the /dev/ttyS0 looks like this:

crw-r-----    1 root     dialout    4,  64  7. Jan 2002  /dev/ttyS0

... and no one can dial in again. I have to change this as root.

What actually does go wrong here? If one would use kppp the problem does 
occur.

Regards,
Alex