Xref: utzoo comp.dcom.lans:2845 comp.misc:6177
Path: utzoo!attcan!uunet!mcvax!ukc!strath-cs!glasgow!bru-cc!tony
From: tony@cc.brunel.ac.uk (Tony Begg)
Newsgroups: comp.dcom.lans,comp.misc
Subject: Re: Installing Thinwire Ethernet
Summary: wallplate to take plug-barrel-plug needed
Message-ID: <722@Terra.cc.brunel.ac.uk>
Date: 22 May 89 11:27:06 GMT
References: <1381@ndmath.UUCP>
Organization: Brunel University, Uxbridge, UK
Lines: 38


I looked for a solution that would not involve extra cable length for
unoccupied offices, and use existing BNC metalware in a cost-effective way.
There just didn't seem to be any appropriate wallplates.  Maybe this AMP
LAN-LINE thing is what I've been looking for but it sounds a bit complex.

In the absence of any neat solution, I have been installing thin ethernet with
a barrel connector in each office, which is broken to connect to equipment,
a second barrel connector used, with standard made up BNC cables and a T
piece at the back of the workstation or whatever.  All that is wrong with
this approach (if you ignore breaking the network to add equipment which a
lot of other solutions share) is it is not particularly neat or mechanically
sound.  I believe it could be made so with a two part injection moulded wall
plate, in the shape of a truncated equilateral triangle (ie sort of hexagonal).

One part screws to the wall and the other part is a cover which is removed
to add or remove equipment.  The BNC plugs with their barrel connector
locate in channels along the sides of the triangle.  An "empty" office has
the single plug-barrel-plug located along the base of the triangle.  To connect
equipment, the barrel is broken, a second barrel added to the free plug, and
these connected to the two device cables, then the two plug-barrel-plug
assemblies located along the other two sides of the triangle, so the twin
cable to the device exits from the "top" of the triangle.  Location would be
in tubular channels in the part of the wall plate screwed to the wall, with
longitudinal restraint by protrusions into the channels that fit the bit of
the BNC plugs with a smaller diameter (where you can see the slot for the
bayonet pin).  I noticed that the length of the various barrel connections was
about constant whereas the diameter of the centre of the barrels varied between
manufacturers, so that this method of restraint is more metalware independent 
than a protrusion between the two plugs.  The triangle would need to be about
5.75 ins along a side, and truncated to give a hexagon with three opposite sides
about 3.25 ins (along which the channels for plug-barrel-plug run) and the other
three sides 1.25 ins (where cables enter and leave).  The wall plate is 3
fold symmetric.  I am trying to convince our Materials Tech department to make
the injection moulding (or a cheaper vacuum formed version).

Of course for the rectilinear minded as long as the channels in the wall
plate formed a triangle, the wall plate could be about 4 ins square.