Problems of /dev/ttyS0 permissions using wvdial

[Francois Fayard <fayard@ens.fr>]

Hello,
I use wmppp to start and stop my ppp-connexion.
Everything works well, but sometimes I have problems with my permissions
on /dev/ttyS0 (my modem) that are changed.
I'm obliged to do a chmod g+rw /dev/ttyS0 to reconfigure my permissions.
my starting script is : wvdial
my stopping script is : kill `ps h --format pid -C wvdial`
I think, the stopping one is no really a good one (It has been made by me...)

Can anyone help me ?
Thanks, Francois