I installed debian and used pppconfig to generate the chat scripts. Everything worked ok.
A little later, I installed a custom kernel using my regular parameters ( ie: moving ppp into the kernel, not a module ). I couldn't connect, or even dial out as far as i could tell. In syslog I find "Chat: can't get terminal parameter: input/output error." But if I boot from the floppy boot disk I made during install, pon/ppp works. The custom kernel is the 2.2r2 source package (2.2.18, from memory) with a security patch that I've used on that machine without problems before. I'm sure I must be missing something configuring the kernel, but I can't catch it. thanks & best wishes, Jon