Wiring BT Extension - Good Job I'm Analytical

[Ninanina]

For the last 10 years I've had a very thin BT extension cable running underneath my carpet as the BT Master Socket enters the house in the opposite corner to where my phone and router are placed

As I have now ordered Fibre broadband I thought it about time I replaced the very thin cable with something more suitable to run around the skirting board/doors so I purchased some genuine BT cable, BT socket and BT plugs

The cable is BT CW1308 4 Core, the socket a BT spec 2/3A IDC slave box and the plugs are BT spec 4 pin 431A's

The genuine BT cable I have is coloured Blue, Brown, Green and Orange

Seriously it was a complete nightmare to find a definitive answer as to how the socket/plug should be wired with this coloured cable as there seems to be many colour combinations available for BT cable

The seller of the items was not much help to be honest

I worked through everything I could find on the net and finally worked it out, what a complete minefield it was

But finally I have a working phone and router ready for my Fibre ;)

[Stratmangler]

First off, well done! Most folk bugger about and usually screw things up.
Second off, why didn't you ask here?

You could have saved yourself a lot of effort - I'm a Telecoms Engineer, and have dealt with stuff like this for 20 years or so, since ADSL first started being used.
I do this kind of thing on a regular basis.
Your previously existing extension cable would have been fine to use, and all you'd have had to do was change the filter from an ADSL one to a VDSL one.

Your fibre connection will be FTTC (Fibre To The Cabinet), which means it will be connected to your local roadside cabinet with vents in it (they are generally right next to cabinets that do not have vents in, and these could have been in situ for 30 years or more), accompanied by stickers with stuff like "Danger Of Death" and "Beware Laser".
From the local cabinet it will use the existing cable to your premises.
Nobody will need to turn up at your door to change anything, and you should receive a new router capable of handling the increased bandwidth through the post.
The VDSL filter should be in the box with your new router.

[Barry]

I did the same as you Bev; replacing a computer/phone extension lead with a hard-wired system incorporating two new sockets. All components were bought from a DIY store (can't remember which one it was) and the terminals of the sockets were marked with the colours of the four wires used in the cable. No problems occured; I checked the first new socket with the phone before I went on to wire up the second.

Anyway, well done - you cracked it Bev!

[Beobloke]

Ah, yes, the fun of moving phone sockets.

Of course, moving the main one is illegal as it is BT's property, but to move it for you they want over £200, according to the nice lady I spoke to in India to raise the possibility of having ours moved. Even she was shocked and asked whether I could do it myself, whereupon I reminded her that only two minutes previously, she had told me that would be illegal!

She also pointed out that if I did choose to have a go and move it myself, but made a mistake and had to call out BT to fix it, they would charge me. When I inquired how much, she told me £85! You really couldn't make this up...

[walpurgis]

Got mine done free. The phone engineer was a dog lover and liked my big lurcher and he appreciated the cuppa 'n biccie I gave him too. He sorted the main socket and incoming connections, rewired to my first extension (which was mine) and said all the problems were outside and I'd not need to worry about being charged! :)

[struth]

First off, well done! Most folk bugger about and usually screw things up.
Second off, why didn't you ask here?

You could have saved yourself a lot of effort - I'm a Telecoms Engineer, and have dealt with stuff like this for 20 years or so, since ADSL first started being used.
I do this kind of thing on a regular basis.
Your previously existing extension cable would have been fine to use, and all you'd have had to do was change the filter from an ADSL one to a VDSL one.

Your fibre connection will be FTTC (Fibre To The Cabinet), which means it will be connected to your local roadside cabinet with vents in it (they are generally right next to cabinets that do not have vents in, and these could have been in situ for 30 years or more), accompanied by stickers with stuff like "Danger Of Death" and "Beware Laser".
From the local cabinet it will use the existing cable to your premises.
Nobody will need to turn up at your door to change anything, and you should receive a new router capable of handling the increased bandwidth through the post.
The VDSL filter should be in the box with your new router.

I had a guy who fitted mine.. first he put the router in and then realised he needed to go get a modem too. no filter so I guess its a filtered faceplate in the new socket he fitted. Took a while but had no trouble in 3/4 years.

[Hammer]

As an ex BT engineer of 35 years i may have been able to help.Glad to hear its ok now

[hifi_dave]

I managed 27 years with BT International.

[Ninanina]

I guess I like a challenge

I thought It'd be simple and all the info is available but it really was a minefield to find a difinitive answer :doh:

I wonder if anyone can say whether I've dont it correctly?

I have wired the extension slave box as follows:

Blue Wire: Terminal 2
Brown Wire: Terminal 3
Green Wire: Terminal 4
Orange Wire: Terminal 5

I have wired the 431A Plug as follows:

Blue Wire: Pin 5
Brown Wire: Pin 4
Green Wire: Pin 3
Orange Wire: Pin 2

This assumes that pin 6 is the pin nearest the side spring on the 431A

Thanks for any confirmation ;)

[Barry]

Does it work with both the phone and your PC? If it does, you've done it correctly.

[Stratmangler]

You have wired it back to front.
You need 2 to 2, 5 to 5, and 3 to 3.
2 & 5 are the speech circuit, and 3 extends the bell circuit.
It's probably easier to move things around at the socket end.

4 is there for historical reasons, and no longer needed, so you can leave it off in the socket.

[Stratmangler]

Is the socket screw terminal, or IDC?
IDC is insulation displacement connection.
IDC means that you do not strip the insulation back - it's push to make, and it's a gas tight connection. It requires a specialised tool.

[Ninanina]

Is the socket screw terminal, or IDC?
IDC is insulation displacement connection.
IDC means that you do not strip the insulation back - it's push to make, and it's a gas tight connection. It requires a specialised tool.

Hi Chris
Thanks for your reply. The socket is IDC and I have the tool for it

Are you able to give exact socket terminal colours I should have and then the same for the 431A plug? Very much appreciated ;)

My OCD won't allow me to have the colours the wrong way round even though I know it'd make no difference as long as they matched both ends :doh:

[Stratmangler]

You have the wires paired out correctly, which is good.
It doesn't matter which way around they go, as long as you get pin 2 on the plug going to pin2 of the socket, etcetera .....

At the socket end you need to connect orange to 2, blue to 5, and green to 3, according to what you posted earlier.


I have wired the extension slave box as follows:

Blue Wire: Terminal 2
Brown Wire: Terminal 3
Green Wire: Terminal 4
Orange Wire: Terminal 5

I have wired the 431A Plug as follows:

Blue Wire: Pin 5
Brown Wire: Pin 4
Green Wire: Pin 3
Orange Wire: Pin 2

[Ninanina]

You have the wires paired out correctly, which is good.
It doesn't matter which way around they go, as long as you get pin 2 on the plug going to pin2 of the socket, etcetera .....

At the socket end you need to connect orange to 2, blue to 5, and green to 3, according to what you posted earlier.

Thank you so much Chris I really appreciate it

I did think it a bit strange that my plug pin number didn't match my socket pin number

So the brown wire and also pin 4 are not used

[Ninanina]

All re-done now and thanks again Chris

In the plug I did connect the Brown wire into pin 4 as it was easier to use it so all 4 lined up properly as you slide them in but didn't connect it at the socket end

Super service Chris :D

[Stratmangler]

A long time ago it used to be used on business PABXs to make the R button work, and permit users to transfer calls. It was known as ER, or earth recall.
The telephone cabling was all connected to a reference ground point via the leg on pin 4.
Most non BT PABXs used TBR (timed break recall), and didn't require the reference ground point.
Over time TBR has been universally adopted.

To answer your question, no, you don't need pin 4 to be connected.
Just leaving it disconnected at the socket will be good enough.
You can connect it if you want, but it'll not be doing anything. It's inconsequential.

[Ninanina]

Thanks Chris

I'll connect it just to tidy it up I think

Well it's all working

http://i.imgur.com/YpyRD6J.gif (https://imgur.com/YpyRD6J)

[Stratmangler]

Thanks Chris

I'll connect it just to tidy it up I think

Well it's all working

http://i.imgur.com/YpyRD6J.gif (https://imgur.com/YpyRD6J)

That's OCD for you - I wouldn't bother.
As for the rest, you're more than welcome :cool: