selecting this option with "make xconfig" leads to complier error when "make modules". The pcmcia part of the source tree does not include support for AVM. See pcmcia-cs-3_0_5_avm_diff.gz for a patch. isdn4k-utils does not compile (fine with S.U.S.E) - cannot find curses.h.
Upgrade to the latest kernel and see if that fixes your problem. Reopen this bug if you are still experiencing problems with the updated kernel.