I've got a similar question.  Right now I'm trying to hook my SE/30 up to
my network through a serial link.  I've found a mac serial -> pc 25 pin
cable and a null modem which I now have hooked between the SE/30 and my
Pentium 166 linux computer.  I'm trying to set up a pppd link between them
so I can get the SE/30 (running NetBSD1.4.2) onto my in-house network,
even if it's only at 9600, until I manage to find an ethernet card for it.

Here are the commands I'm running:

on the server (linux box):
pppd -detach crtscts local proxyarp 10.0.0.1:10.0.0.100 /dev/ttyS1 9600

on the client (SE/30):
pppd -detach crtscts local defaultroute 10.0.0.100:10.0.0.1 /dev/tty00 9600

After about 30 seconds, both systems time out with:

Using interface ppp0
Connect: ppp0 <--> /dev/ttyS1
LCP: timeout sending Config-Requests
Connection terminated.

Do I have to do something special to get the serial ports to talk to each
other?

~~~~~~~~~~~~~
Sean Murphy
 Unix Security Underling
  Canadian Bioinformatics Resource
~~~~~~~~~~~~~
perl - because life is too short to debug pointers and memory allocation