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From: cmilono@netcom.UUCP (Carlo Milono)
Newsgroups: comp.dcom.lans
Subject: Re: PC/AT Ethernet interfaces w 10BaseT transceiver built in?
Message-ID: <12953@netcom.UUCP>
Date: 30 Aug 90 22:55:31 GMT
References: <1990Aug30.002629.21682@grian.cps.altadena.ca.us> <1990Aug29.223110.27185@hellgate.utah.edu> <1990Aug30.092313@synoptics.com>
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Lines: 36



Add to this list Hewlett-Packard, whose Ms. Thayer chairs the IEEE committee
and who, along with others *rejected* the first Synoptics proposal - note
that there is NO SUCH THING as a concentrator in the specs.  And don't forget
AT&T's StarLAN 10, which won the LAN Magazine Drag Race and subsequently the
Ethernet Product of 1989.

Historically, there have been roughly six major proposals for the standard:

AUI1	 H-P	      2-pair MAU-MAU with AUI Interface with MPR 
AUI2     Synoptics    concentrator without retiming
Sync	 Chipcom      Synchronous Manchester coding
AUI/Coax 3COM/DEC     Pair-tamer extension of 10BASE2
Mod Man  David Sys    Asymmetric  MAU's different at each end
OQPK	 Rypinski     QPSK (quickly rejected)

Until recently, Synoptics and Cabletron both offered incompatible equipment
with any other vendor's - problems with Receive Equalization and voltage
levels with Synoptics (along with the use of concentrator technology) and
Idle Signal use, respectively.  I understand that they now support *true*
interoperable 10BASET products (incompatible with their previous line).

This is one of the problems of being 'first to market/first to buy'.

Also, be aware that FCC registration and actual FCC compliance of Rack
style MPR's are two different things - I sincerely doubt that any Rack
unit, although stickered and given an FCC number, would actually pass
the stringent tests in the real world.
-- 
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|                   Carlo Milono                                           |
|    Personal:    netcom!cmilono@apple.com   or   apple!netcom!cmilono     |
|"Sometimes I think the surest sign that intelligent life exists elsewhere |
| in the universe is that none of it has tried to contact us." B.Watterson |
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