I've been struggling with connection Asterisk to ISDN BRI lines for a while. I have it working with the latest bristuff and compatible Asterisk version: Asterisk 1.0.3-BRIstuffed-0.2.0-RC3a I am using a cheap Centronics ISDN card and the zaphfc drivers. It works but users complain that the sound quality is not good. They have Xlite phones on their desktops. Xlite to Xlite through Asterisk is fine. Xlite to PSTN through ISDN is not good. Anyone got any experience with this kind of setup and improving sound quality? I will add anything new info to the Wiki.