same Problem for me too

wihle trying to configure with isdn-config there where not entries in /var/log/messages

I then tried to start isdn as root "/etc/init.d/isdn start", after that I tried to dial with "isdnctrl dial ippp0".
In /var/log/messages you can see that there is an attempt to dial but it ends up with
"fcpcipnp0,ch0 cause E001B"

in "man isdn_cause" this meens error location from user (I think my PC) and cause "Destination out of order"

Any hints ???

Thanx,
Achim