Hello,

to make things clearer what happens on my side:
I have 2 PCI Cards sharing the same IRQ11 (my Video-Card and the FritzCard ISDN-Controller) and I have suse 6.3, suse 7.2 and suse 9.2 installed on my system. Using the suse-distributions I have no problem to connect to my provider.
At the moment I think the problem with debian/knoppix is in the "handling" of pci or interrupts but I don't know the modules responsible for that.

There is one last thing I could try: change the physical slot of the ISDN FritzCard, but because the system ddoes well with suse I don't want to to that.

@zip.it and raphaelmack:
try to install with the debian "isdnconfig", this is only text-based but it seems that the right config-files will be written with this tool.