In /etc/init.d/isdn you are checking for the value 'out' in $SECURE
| if [ "$SECURE" = "out" ]; then
| log_isdnctrl secure $device $SECURE
isdnctrl doesn't accept 'out' as value at `secure':
| $ ./isdnctrl secure ippp1 out
| Secure-parameter must be 'on' or 'off'
Probably you are meaning `off'.
I have fixed it. Thanks.