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From: phil@amdcad.UUCP (Phil Ngai)
Newsgroups: net.lan
Subject: Re: How do I cable an Ethernet?
Message-ID: <11599@amdcad.UUCP>
Date: Wed, 7-May-86 15:59:50 EDT
Article-I.D.: amdcad.11599
Posted: Wed May  7 15:59:50 1986
Date-Received: Thu, 8-May-86 22:04:38 EDT
References: <546@rdin.UUCP>
Reply-To: phil@amdcad.UUCP (Phil Ngai)
Organization: AMD, Sunnyvale, California
Lines: 28

In article <546@rdin.UUCP> perl@rdin.UUCP (Robert Perlberg) writes:
>Is there any truth to the rumor I heard that plain RS-232 type cable
>can be used to connect Ethernet transceivers?

You could probably use telephone cable if it was short enough.  (six
inches?) "plain RS-232 type cable" is pretty ambigious.  I have been
tempted to use Belden 9891 Ethernet transceiver cable for RS-232.
Clearly I could convert that "RS-232" cable for transceiver cable use.
I have seen people use short lengths of flat ribbon cable for
transceiver cables (Interlan).

If you are going 50 meters then things get a little tougher.

The main considerations are that you need to supply 500 mA over 50
meters with only 2 volts of loss for the power and that the signals
are differential so you ought to use twisted pair for the
transmit/receive/collision signals. There are also crosstalk
requirements which are usually met by shielding each pair and then
shielding the entire cable as well.

IEEE 802.3 adds a fifth pair but I don't know if anyone uses it yet.
Anyone seen it?
-- 
 If a reactor melts down in Russia will they call it the America syndrome?

 Phil Ngai +1 408 749 5720
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