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From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: comp.dcom.lans
Subject: Re: ST or SMA fiber connectors
Summary: FDDI uses MIC's
Message-ID: <61655@sgi.sgi.com>
Date: 5 Jun 90 19:03:18 GMT
References: <30971@ut-emx.UUCP>
Sender: vjs@rhyolite.wpd.sgi.com
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 30

In article <30971@ut-emx.UUCP>, blais@ut-emx.UUCP (Donald Blais) writes:
> Vendors of fiber optic cabling and fiber optic transceivers often
> provide the option of using SMA or ST connectors.  In selecting a
> standard for a site where no standard is yet established, why should
> one choose ST over SMA or vice versa.  The application, in this case,
> would be a large campus Ethernet data distribution system that would
> later be upgraded for FDDI.
> -- 
> Donald E. Blais             Internet: blais@emx.utexas.edu


The FDDI standard requires neither STs nor SMAs, but MICs.

Much of the FDDI hardware now being shipped uses STs, often hidden behind
the shells that turn a pair of ST plugs into a MIC recepticle.  I do not
know if such shells are available for anything except STs.

If you use STs now, you can later use such shells and some short MIC jumper
cables to convert your cable plant.  It would cost the insertion loss of an
extra connector, but would be easier and could be cheaper than
reterminating.  (Actually, unless you are good with the polishing pads, you
might have less insertion loss with two machine terminations than with one
field termination, and so might come out ahead in loss budget by using such
jumpers.)  Also, if you use STs, you might be able to connect them directly
to your FDDI equipment, after discarding a shell or jumper cable.


Vernon Schryver
Silicon Graphics
vjs@sgi.com