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From: hagan@hagan.dccs.upenn.edu (John Dotts Hagan)
Newsgroups: comp.dcom.lans
Subject: Re: Twisted Pair Ether query
Message-ID: <13974@netnews.upenn.edu>
Date: 30 Aug 89 07:05:18 GMT
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Reply-To: hagan@dccs.upenn.edu (John Dotts Hagan)
Organization: University of Pennsylvania
Lines: 32

I have had quite a few debates and discussion with vendors, and other
people responsible for campus networks, about the use of twisted pair
ethernet vs. Thinwire ethernet (RG58 coax).

I have always favored the coax, because we always seem to have to install new
wire to support every new station, since we can never find where old (pre our
group wiring the campus) copper wire goes.

The cost to install thinwire vs. twisted pair is not large, since the bulk of
our cost is the labor to install.

Our standard wiring is to pull tree kinds of wire to all stations: RG58 coax,
and both shielded and unshielded 22 guage twisted pair.  The shielded wire
is up to IBM's 16 Megabit specs, but we have never used the IBM token ring
over that wire.  Sometimes we use the shielded for a second asynch connection,
although the shield causes some problems over long runs.  We also pull
telco wire, if we are in a new building and our telco group works with us.  We
have also planed for video, but never installed it.  Finally, whenever we put
in conduit for the wire, we make sure it could hold fiber (no bad bends).

Anyway, I believe the twisted pair solutions are near the capacity of twisted
pair, and some products have distance limits that are close to some of our
longer station to closet runs.  However, RG58 has no trouble reaching any
desk.

My final trump card is I hope that some smart vendor makes a faster version
of ethernet (or even FDDI) that can run over RG58 coax.  I think anything in
the range of 100 Megabits is next to impossible for the twisted pair in our
walls, but should be quite possible over the coax.  So maybe we won't need to
rewire for fiber to all desks to get at least FDDI-like speeds.

--Kid.