In message <199609210618.JAA16074@pyy.jmp.fi>, Jukka Marin writes:
>Put something like this in your /etc/gettytab:
>mod.19200:\
>        :nl:np:tt=vt100:sp#19200:to#60:....
>Next, change your tty entry in /etc/ttys to use this definition (mod.19200
>like I call it).  kill -HUP 1 (yes, this time it does the trick) and you
>should have an 8N1 connection.

Yeah, I got an 8N1, and unfortunately it still exhibits the weird 
behavior; I cannot set the vt100 for 9600bps (well I can, it just won't
communicate properly).  Also, if I disable "Auto XON/XOFF", an "ls -la"
will make it hose up with framing/parity errors (checkerboard characters).
I figure that's okay; without hardware flow control I guess you have
to use XON/XOFF or just be really fast.
Finally, the weird part is that if I type while receiving output,
the rest of the output gets all garbled (again, those checkerboard
characters and junk).  This is obviously not good, but tolerable.

Anyway, at least it's working; a big thanks to everyone who helped.
"ttyflags -a", not "kill -s HUP 1", was the key...