I cannot access /dev/tty/AMA0 anymore.
ls -l /dev/ttyAMA0
crwxrwx--- 1 root uucp 204, 64 Sep 25 22:10 /dev/ttyAMA0
[cb@m]$ groups cb
uucp audio users
[cb@m]$ cat /dev/ttyAMA0
cat: /dev/ttyAMA0: Permission denied
obviously cb is member of uucp and should be allowed to access /dev/ttyAMA0.
If I change the access right to allow access for everybody (chmod 666 /dev/ttyAMA0)
I can access the port without problems, but this is not what I want to do as everybody can access
/dev/ttyAMA0 in this case.