Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!mstar!mstar.morningstar.com!bob
From: bob@MorningStar.Com (Bob Sutterfield)
Newsgroups: comp.dcom.lans
Subject: Re: Can I "null-modem" 15 wire Ethernet or build my own xceiver?
Message-ID: <BOB.90Jul24163338@volitans.MorningStar.Com>
Date: 24 Jul 90 20:34:05 GMT
References: <620@beguine.UUCP>
Sender: usenet@MorningStar.COM (USENET Administrator)
Reply-To: bob@MorningStar.Com (Bob Sutterfield)
Organization: Morning Star Technologies
Lines: 24
In-Reply-To: Jeff.Miller@samba.acs.unc.edu's message of 24 Jul 90 09:02:54 GMT

In article <620@beguine.UUCP> Jeff.Miller@samba.acs.unc.edu (BBS Account) writes:
   Does anyone know how to "null-modem" a pair of machines together
   using the 15 conductor standard? I only need to go a couple feet. I
   would assume if it is possible it would only work point-point.

Nope, you'll still need a transceiver, or its moral equivalent, for
each node.  The bad news is that the initial investment just to get
two boxes talking on Ethernet is rather high.  Your best bet will be
to buy two thin Ethernet transceivers, a hunk of RG58 coax, a pair of
BNC T-connectors, and a pair of 50 Ohm BNC terminators.  The good news
is that you'll then have a fully-functional Ethernet on your desk,
with all the rights and privileges appertaining thereto.  It will be
much easier to add the third box than if you had only created a "null
modem" transceiver cable.

   Also, I bet several manufacturers have wasted no time coming up
   with single-chip transceivers that need few external parts. Anyone
   familiar with any of these, know any part numbers, or know a source
   for small quantities?

See recent discussions in comp.sys.sun for lists of companies
producing very small (credit card size), very low-cost ($120-200)
thinnet transceivers.  One of their big markets is for Sun
SPARCstations and SLCs with only AUI ports from the factory.