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From: leong@PO1.ANDREW.CMU.EDU (John Leong)
Newsgroups: mod.protocols.tcp-ip
Subject: Re: Fiber-optic Ethernet Extender
Message-ID: <8605220232.AA07216@ucbvax.Berkeley.EDU>
Date: Wed, 21-May-86 18:41:36 EDT
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Posted: Wed May 21 18:41:36 1986
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DEC, Ungermann-Bass (UB) and American Photonics (API) make both local
and remote repeaters. 

All the remote repeaters use fibre optic cables. DEC and UB requires
100 micron cable while API is engineered for 50 micron. (Phone companies
had been busy putting in 50 micron cables. They are now changing to
62.5). One thing you should know is that when you connect a 100 micron
light source into a 50 micron cable, you lose 75% of your light !!!  

API has an Ethernet extender which is really a long fibre drop cable
transceiver and is quite cute.

If you want to join two nets together but do not want to sum up the
traffic, you can investigate into the LANbridge from DEC. They sell
both a local as well as a remote version (or you can use a local version
with the API Ethernet extender). I really like the LANbridge better
than plain repeater since they will relay only applicable packets to
the other side. However, they do cost $$$$. (roughly $8,000 list)

John Leong