Extension Cable Damaged

[Earlofdon]

Apologies in advance as the question concerns a modern problem which I'm hoping that somebody can kindly advise upon.

In short, I've snapped the extension cable which connects the main BT socket box in the hallway with an extension socket upstairs.
I haven't a clue how to reconnect the wiring, but do have an additional socket. Can I use this to bridge the connection by connecting the two half one how?

Many thanks.

[AC/HL]

http://www.telephonesuk.co.uk/wiring_info.htm

[mike_newcomb]

Hi Earl, check the existing connections.
Generally 4 same pin to pin connections are made, although 6 are available.
However only 3 or sometimes 2 (ring signal depending on phone) are used:-
1 not used
2 to 2
3 to 3
4 to 4
5 to 5
6 not used

You need check the spare box you have is a Slave (missing few Components) and not a Master (has Components). Look in existing boxes and you should see what I mean.

Instead of Bill's link, I think it better explained / illustrated here:-

http://www.wppltd.demon.co.uk/WPP/Wi...telephone.html

Regards - Mike

[Biggles]

A neat solution is to use a 6-way junction box, can't remember the BT number off hand but they should be available from DIY outlets etc. They are small so unobtrusive but you may not have enough spare cable at the break to reach the terminal. If that's the case you could use two junction boxes with a bit of 6-way cable between the two. You should be ok just joining colour for colour in the cable.
Alan.

[Dave Moll]

I would have thought you would only need four-way cable between your two junction boxes - leaving two terminals in each box unused.

[G6Tanuki]

I've only ever done extensions in 2-wire.

The third 'bell' wire's a legacy and not needed for any phone made since about 1980 - indeed, it can cause significant signal/throughput issues when you want to run an ADSL connection from the extension-outlet.

[Oldcodger]

Originally Posted by Biggles

A neat solution is to use a 6-way junction box, can't remember the BT number off hand but they should be available from DIY outlets etc.

Box connection 77a for 6w cable/78a for 8w cable. The cable can be punched straight in using a DECENT IDC tool in the commercial ones, but if you get one with BT markings on it, they USED to need the wires thread under a bar on the terminals.
In essence, as has been said, you only need three wires for an extension. Simply open the socketc before and after the break and note the colours of the wires on terminals 2,3,5 and connect these three through. Try extension after join for dial tone and then ring house phone from mobile. No ring- check the EXACT colour markings on the wire on terminal 3, and that you have not crossed the wire colours on terminals 2 & 5.
If the wires are not long enough to connect through using one box, it might be neater and cheaper ,to buy just one box and a metre of 6w telephone cable and terminate one end on terminals 1,2,3, and the others on 4/5/6, and use individual wires from the metre of cable to bridge the corresponding colours. ( e.g., if you put white/blue on terminals 1 & 6, then use same colour to connect these terminals together.

[Earlofdon]

Thanks for the replies, much appreciated.

The socket that I have is the one shown.

Do I connect one half of the wiring into terminals 1,2 and 3 with the other half being connected to 4,5 and 6?

Many thanks,

Chris

[Outrun_uk]

Originally Posted by G6Tanuki

The third 'bell' wire's a legacy and not needed for any phone made since about 1980 - indeed, it can cause significant signal/throughput issues when you want to run an ADSL connection from the extension-outlet.

That may be very helpful for me, my brother is having speed issues with his broadband. I replaced a junction box with corroded terminals but have always wired the third connection so will pop down and disconnect it

Cheers,

Kev

[Pellseinydd]

Originally Posted by G6Tanuki

I've only ever done extensions in 2-wire.

The third 'bell' wire's a legacy and not needed for any phone made since about 1980 - indeed, it can cause significant signal/throughput issues when you want to run an ADSL connection from the extension-outlet.

The third wire was definitely required for approved phones manufactured long after 1980. The modern 'plug & socket' system wasn't introduced until November 1981 although I first saw the sockets in mid-1980 when I collected the first samples made for Plessey from the manufacturers Austin Taylor at Bethesda in North Wales for onward delivery to Plessey's at Beeston.

BT's 87XX series of phones weren't produced until after 1980 and many were made new after that date. Also 'approved' privately produced after 1980 phones also required the third 'bell' wire until long after then.

It was a common problem with wiring used with phones made well after 1980 - I spent many years after 1980 maintaining phones/systems.

The 'two wire' phones around c1980 were the 'unapproved' ones sold by the likes of Tandy and usually brought in from the USA/Far East. Often caused 'bell tinkle when used with pulse dialling. Hence the reason for the third 'bell' wire from 3 to 3 between the master socket and subsequent sockets.

In recent years, with the virtual disappearance of pulse dialling phones, the bell tinkle problem has disappeared.

As most ADSL filters have the capacitor to 'filter off' the bell wire incorporated within, it is possible to use just two wires. See http://www.sinet.bt.com/sinet/SINs/pdf/351v4p6.pdf for the 'official' BT way.

[Nickthedentist]

Originally Posted by Earlofdon

Do I connect one half of the wiring into terminals 1,2 and 3 with the other half being connected to 4,5 and 6?

No, connect one half to 2/3/5 and the other half to 2/3/5 as well, leaving 1/4/6 empty:

Originally Posted by Oldcodger

In essence, as has been said, you only need three wires for an extension. Simply open the socketc before and after the break and note the colours of the wires on terminals 2,3,5 and connect these three through.

[Oldcodger]

Originally Posted by Earlofdon

The socket that I have is the one shown.

Do I connect one half of the wiring into terminals 1,2 and 3 with the other half being connected to 4,5 and 6?

My advice was based on the idea that you may have problems with length of wires. So connect one side to terminals 1/2/3 , and the other side to 4/5/6, and use single cores from the metre length to connect LIKE colours to each other.

[Earlofdon]

Many thanks for the replies