Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!bu-cs!mirror!ima!haddock!jimm
From: jimm@haddock.ima.isc.com (Jim McGrath)
Newsgroups: comp.dcom.lans
Subject: Re: Req For Info - Ethernet Electrical Rules/Specs
Message-ID: <14936@haddock.ima.isc.com>
Date: 20 Oct 89 17:48:40 GMT
References: <188.2526de30@acci.com> <580@trwind.UUCP> <850@maxim.erbe.se> <410@wcc.oz>
Reply-To: jimm@haddock.ima.isc.com (Jim McGrath)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 17

In article <410@wcc.oz> tom@wcc.oz (Tom Evans) writes:
>
>OK. What we ALL want (:-) is to have the cheapernet in the wall where
>it can't be broken, tripped over, left unconnected. What we want is
>a BNC on the wall, one on the back of the machine and a simple cable
>connecting the two. Too bad the electrical specs won't allow it
>
I recently ran across a product from AMP that provides this
capability.  It consists of a wall plate assembly and drop cable.  The
drop cable is really a double length coax, and thus increases your
segment length by twice the length of the drop.  There is an
application note (DP 5727) that should be reviewed to get an
understanding of potential problems, e.g. reflections caused by
impedence mismatch since both segment and drop may have a mismatch of
as much as 4 ohms (the standard is 50 ohms +- 2).

Jim