RE: BT Master Socket - Comfort - ADSL etc etc etc

["Nigel Giddings" <nigel@xxxxxxxxxxxxxx>]

Hi Ben,



I see what that are doing. The comfort ringer module outputs the ringing
on the 'B' Wire (the speech pair from the telephone exchange has an 'A'
wire (earth when idle) and a 'B' wire (Battery which is -ve 50v when
idle)).



When BT came up with the 3 wire system (only used in the UK I believe)
they decided to arrange things so that ringing would be distributed on a
third wire which prevents the bells 'tinkling' during loop disconnect
dialing and when Handsets are taken Off Hook and put On Hook... It is
the job of the Master socket to pass the ringing from the incoming pair
to the 3rd wire and on to the phones. The phone handsets are then wired
so that the bells are connected to wire 3 and not across the pair as is
normal practice elsewhere in the world... A lot of this is academic now
as many BT approved phones will work with and without a Master Socket,
they suppress the 'tinkling' electronically. When the 3 wire system was
designed phones were very basic internally :-)



To enable internal phones (that comply to BT design) to be able to ring
from Comfort you must get the 'Comfort Ringing' off of the 'B' Wire
where comfort puts it onto the internal ringing wire (wire 3). To do
this you put a capacitor between the 'B' wire and the ringing wire, this
is what a 'Master socket does. Ringing current is 75V AC 25 Hz so will
pass through the capacitor whereas the DC signaling (On Hook, Off Hook
and loop disconnect dialing when we had dials) will not pass onto the
third wire and therefore does not cause the bells to 'tinkle'.



The second diagram (http://www.comfort.org.uk/images/supp1.gif)
will
work but you will have more capacitance across the line than the BT
expects and it may affect any testing they do, ie give results out of
limits.



Is this making more sense?



Nigel



-----Original Message-----
From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
Of Ben McCormack
Sent: 23 June 2008 15:55
To: ukha_d@xxxxxxx
Subject: Re: [ukha_d] BT Master Socket - Comfort - ADSL etc etc etc



Nigel

I am now confused!! - The comfort manual mentions 2 BT Master Sockets

http://www.comfort.org.uk/images/supp11.gif
<http://www.comfort.org.uk/images/supp11.gif>
http://www.comfort.org.uk/images/supp1.gif
<http://www.comfort.org.uk/images/supp1.gif>

I have also found that to comply as much as possible with BT Wiring
standards I should be using CW1308 cable to extend the run to node zero.

Ben

On 23 Jun 2008, at 15:47, Nigel Giddings wrote:

> Ben,
>
> What you suggest sounds fine in principle except for installing two
> master sockets. You will only need one, installing two will add more
> capacitance to the line which should be avoided. When routing through
> comfort you have the Tel In and Tel out connections which are 2 wires
> only, you need to keep the third wire connected through comfort and
> pass
> all three wires to all slave sockets... Hope this makes sense.
> Remember
> to maintain the twisted pair on the voice pair and to run the ringing
> wire in a separate pair. If you do not respect the pairs your phones
> will suffer interference from electrical equipment...
>
> Nigel
>
> -----Original Message-----
> From: ukha_d@xxxxxxx <mailto:ukha_d%40yahoogroups.com>
[mailto:ukha_d@xxxxxxx
<mailto:ukha_d%40yahoogroups.com>
] On
Behalf
> Of Ben McCormack
> Sent: 23 June 2008 14:59
> To: UKHA Mailinglist
> Subject: [ukha_d] BT Master Socket - Comfort - ADSL etc etc etc
>
> All
>
> I am trying to get my head around the wiring I need to do for the BT
> Master Socket, Comfort and ADSL.
>
> The current situation is as follows
>
> Incoming BT Line into a very old BT Connection Box then onto BT Master
> Socket in the Lounge.
>
> I would like to achieve the following
>
> Current Master BT Socket is in the wrong place - I would like it to be
> in the new node zero location about 20m away
> ADSL Router also located in Node Zero
> Telephone Wiring to Comfort that is also located in Node Zero (Comfort
> has ringer module)
> Telephone will be distributed over Cat5 Structured wiring
>
> I know playing with the BT Socket is wrong but I would like to do the
> following
>
> Take Incoming BT line and join to CAT5 to node Zero using Krone
> Punchdown connection Box
> (http://www.tlc-direct.co.uk/Products/GPJB1.html
<http://www.tlc-direct.co.uk/Products/GPJB1.html>
> <http://www.tlc-direct.co.uk/Products/GPJB1.html
<http://www.tlc-direct.co.uk/Products/GPJB1.html>
>
> )
>
> Once in Node Zero wire Cat5 into BT Master Socket and use ADSL
> Faceplate splitter to feed to ADSL Router
>
> Wire Voice Connections into Comfort tel in
>
> Wire from Comfort tel out to secondary BT Master Socket
>
> From the secondary BT Master Socket wire into the structured wiring
> to distribute the voice connections
>
> Now I have 2 questions
>
> 1. Will this all work? and is this a sensible way of doing it all?
>
> 2. I am not 100% sure of the connections on the Comfort side. I have
> been looking at the following wiring diagram
>
> I think it all makes sense apart from this business of having to
> connect the pin 3 (Ringer) Between the 2 Master Sockets. How do I make
> this in reality? I cant think of a way of doing it without it becoming
> messy?
>
> Cheers
> Ben
>
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>
> [Non-text portions of this message have been removed]
>
>
>

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