Well, I switched back to pppd 2.3.0b5, but the result was the same...

Sep 30 18:39:36 acheron pppd[1330]: pppd 2.3.0b5 started by mason, uid 0
Sep 30 18:39:40 acheron pppd[1330]: Serial connection established.
Sep 30 18:39:41 acheron pppd[1330]: Using interface ppp0
Sep 30 18:39:41 acheron pppd[1330]: Connect: ppp0 <--> /dev/tty01
Sep 30 18:39:41 acheron pppd[1330]: Serial line is looped back.
Sep 30 18:39:42 acheron pppd[1330]: Connection terminated.
Sep 30 18:39:45 acheron pppd[1330]: Terminating on signal 15.
Sep 30 18:39:45 acheron pppd[1330]: disconnect script failed
Sep 30 18:39:46 acheron pppd[1330]: Exit.

This would seem to imply that something else has changed. Anyway, I'm going
to try to figure out what's up, but I'm beyond my depth here, for the
moment, anyway.

One odd thing I noticed is that /dev/tty0? had owner 'uucp', and not owner
'root'. However, chowning the device files didn't have any effect on things.

I can talk to my modem successfully with uucp, and I can even cat commands
to /dev/tty01 successfully, but pppd won't talk, which annoys me somewhat.

Thanks in advance for the help. :)

--
        Mason Loring Bliss    /\    mason@acheron.middleboro.ma.us
     www.webtrek.com/mason   /()\   awake ? sleep() : dream();
<barbaric>YAWP!</barbaric>  /    \  Squeak to me of love!