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From: bruce@camb.com (Barton F. Bruce)
Newsgroups: comp.dcom.sys.cisco
Subject: Re: What about ground loops?
Message-ID: <1991May14.034137.39733@camb.com>
Date: 14 May 91 03:41:36 EST
References: <22713@yunexus.YorkU.CA>
Organization: Cambridge Computer Associates, Inc.
Lines: 17

>   Something struck me when I was wiring the console ports of a set of
> machines to a terminal server:  why was I connecting the terminal server 
> via optoisolators?  

DEC does push their credibility gap a bit wider with their VCS recomendations.

They are giving you a configuration that is supposed to be VERY conservative
and safe and reliable. Needlessly so as you have noticed. Many have safely
ignored their suggestions. Many have found that their fiber got knocked 
about too much and IT proved to be a very weak link when it BREAKS.

If you are in an environment where ground potential is SO different
between say another cluster on the other side of your arc furnace in your 
steel mill and where you are, use fiber for your ENET, and stick the remote 
console ports on a terminal server over at the other cluster. Don't use fiber
for console ports themselves, especially in a typical computer room or average 
building. Just ignore DEC.