On Fri, 25 Feb 2005 23:19:12 +0000 (GMT), "Dave Plowman (News)"
wrote:


Interesting. What's the BS numbering? And did it apply to domestic
installations?

By a masterpiece of technical superiority, between them the BSI and
BT managed to number the 431A plug in the British Standard as a
mirror image of the socket, so when inserted pin 1 on the plug goes
to pin 6 on the socket, pin 2 to pin 5 and so on.

The pin numbering isn't shown on the plug but many packets of plugs
in the DIY sheds come with a little diagram on the back which often
follows the BS numbering.

If you do the logical thing and put a plug on assuming the numbers
are as on the socket the phone may not ring. Just to confuse the
issue further some imported sockets also invert the numbering so if
you wire pin 1 on an NTE5 master socket to pin 1 on a Chinese (insert
shed name here) socket it may well be going to 6 :-).

A simple way of remembering the correct orientation for the BT plugs
if you like mnemonics is Ring on the Right. When you are holding the
plug with the latch on the right the ring terminal (4 on the plug, 3
on the socket) is always just right of centre.


--
Peter Parry WPP Ltd http://www.wpp.ltd.uk
Antenna solutions for car, caravan, house, office, boat and tent.
Fixed Telephone wiring guide at :-
http://www.wppltd.demon.co.uk/WPP/Wi...telephone.html