Telephone cable booboo

[88v8]

BT socket box for phone extension. What I think of as an RJ11.
Network cable to the box trailing down the (stone) wall.
Some stonework being done a few weeks ago, so I took the opportunity of burying another cable in the pointing. Couldn't bury the original cable as it's too short to follow the wiggly path amongst the stones.

Now I come to connect it up, I find the existing cable has six wires, but the cable I buried, which came from my old cables rummage box, only has four.
Booboo.
Can't get it out again without chopping several feet of lime pointing.

However, I gather that I don't actually need six wires. If so, to connect the four-wire cable to the BT box, which ones can I omit?

V8

 

[rsgaz]

Just to clarify, you don't have the 6 core cable at all any more? You have totally replaced the cable from the master socket to the extension you are talking about with the new 4 core? (i.e. no joins halfway to deal with)

which ones can I omit?

You only need to connect one pair. to pins 2 and 5, at the master(the lower half removable bit) and the extension.

I hope the cable is 24AWG, solid core, twisted pair?

 

[88v8]

Thankyou.
No, I just have to replace four feet of cable where it drops down from the ceiling. I will cut the 6-core cable at the ceiling and put in a 20/4 GPO junction box and connect to the 4-core. Then the 4-core will connect to the BT extension box.

The 4-core is an old GPO phone cable, I do not know the gauge.

V8

 

[rsgaz]

I will cut the 6-core cable at the ceiling and put in a 20/4 GPO junction box and connect to the 4-core. Then the 4-core will connect to the BT extension box

That's fine. Just open up the master to see which pair goes to pins 2 & 5 (hopefully 2 is blue and 5 is white-blue) and replicate that at the join and at the extension.

 

[88v8]

After a near disaster when my auto stripper cut through the wire, it worked.
I discarded 4 & 6.

Mind you, this did not initially go well. As soon as I discarded any wire, the phone would not dial out properly. Then I noticed a button underneath - Tone/Pulse. Wossat, thought I.

Amateurs, eh?

V8

 

[Taser]

The Master socket needs to connect to the incoming BT feeder cable with 2 wires onto either 2 & 5 or A & B depending on type.
To then connect a further extension(s) from this, you need to connect 2,5 and 3 from the master socket to the same terminals in the extension socket(s).
The extension socket(s) should be missing the capacitor, resistor and surge arrestor components (only the master should have these). if they are present, snip them out.
With modern equipment you 'should' be able to get away without connecting pin3 at a push but some older devices may need this to ring correctly and some (older still) may do all sorts of weird things when you dial out.

I'm glad your autostripper didn't leave you with just 2mm of bare cable protruding from your newly formed concrete wall! That should give you a clue as to the luck I normally have.