Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rpi!zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!decwrl!sgi!zok!wattres!steve
From: steve@wattres.UUCP (Steve Watt)
Newsgroups: comp.unix.ultrix
Subject: Re: Serial problems on DecStations?
Message-ID: <423@wattres.UUCP>
Date: 17 Feb 90 08:39:20 GMT
References: <422@wattres.UUCP>
Reply-To: steve@wattres.UUCP (Steve Watt)
Organization: Steven Watt, Consultant
Lines: 17

In article <422@wattres.UUCP> I wrote:
>I was trying to get a Ventel Pathfinder 18K up on a DecStation 3100 running

I have discovered why this doesn't work:  If you hang an oscilloscope off of
the serial port on the DECStation 3100, you see a voltage swing of -5v to +5v
!!!  I realize that this is "officially" allowed in RS232-C, (but not -D), but
the "usually accepted" value is somewhere around +-12v.  The VAXStation 3100, 
incidentally, swings +-10v, which works OK.  My portable swings +-8v, which
also works.

Does anybody know if there is some way to coax more voltage swing out of these
things, or do I get to do some electronic design?  (Like buying from SGI?  :)

-- 
Steve Watt
...!claris!wattres!steve        wattres!steve@claris.com is reported to work.
Is rm -rf a way to remove high-frequency noise?  (No names mentioned!  :-)