Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!labrea!Portia!Jessica!morgan
From: morgan@Jessica.stanford.edu (RL "Bob" Morgan)
Newsgroups: comp.dcom.lans
Subject: Re: Thin Ethernet cable ??
Message-ID: <898@Portia.Stanford.EDU>
Date: 14 Mar 89 20:13:51 GMT
References: <750@aber-cs.UUCP> <858@Portia.Stanford.EDU> <9113@j.cc.purdue.edu>
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Reply-To: morgan@Jessica.stanford.edu (RL "Bob" Morgan)
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In article <9113@j.cc.purdue.edu> tim@j.cc.purdue.edu (Timothy Lange) writes:

>An interesting note to the length and type of thin Ethernet cable
>discussion.  In all my Novell Netware manuals, the supplement for 3Com
>Ethernet cards states that the maximum segment length for thin
>Ethernet is 1000 feet.  Two repeaters may be used to extend to 3000
>feet.  A thick Ethernet segment may go to 3200 feet.
>185M is much less than 1000 feet, what gives??

3Com's claim is that their transceiver design is superior, so that
their units will work on a thin-net segment up to 1000 feet long,
despite the IEEE 802.3 10Base2 spec being 185 meters (~600 feet).  But
"work" means communicate with each other, not necessarily with other
brands of transceiver on the same 1000 foot segment.  We try to keep
our segments well under 600 feet, to maximize the likelihood of
everyone's transceivers interoperating correctly.

BTW, I seem to recall that the Western Digital 8003E has a jumper to
set "long-cable mode" (or something like that) vs. normal mode, which
is supposed to make it work at 1000 feet also.  I never figured out
why you'd want to *not* have it work at the longer length.  Anybody
know? 

 - RL "Bob" Morgan
   Networking Systems
   Stanford