SLIP down for 30 sec once every 180 sec!!

[E Drew Einhorn ADV.SCI.Inc]

My slip connection goes down for 30 sec once every 180 sec.  I have
tried the connection at 9600 and 19200, the results are identical.
Tests are done by doing a ping -sv from each end of the link to the
host at the opposite end of the link.  The machines are connected by a
null modem cable.

One machine is a Sparcstation 1.  The other is a Mac IIci.  The Mac is
running A/UX 2.0.  I am using the slip executables provided by Apple.
The Sun is running SunOS 4.0.3c.  The slip is the version by Rayan
Zachariassen of the University of Toronto.

How can I determine which machine is causing the problem?  I hope it's
the Sun, cause I have the source and can probably fix it once I
diagnose the problem.  If it's on the Mac end I'll may have to wait for
Apple to get around to fixing it.

--
 einhorn at hydra.unm.edu