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Discuss Cut Telephone cable: need to rewire in the DIY Electrical Forum area at ElectriciansForums.net


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So far I'm struggling to identify the cable in use here. I've attached a photo, could someone point me in the right direction of a wiring reference guide so I can attach a standard telephone socket for broadband?



please let me back in to the prison cell.
Electrician's Arms
looking at the number of tails for the bt ,it would be advisable to get in open reach ,looking at the amount of colours on that cable it could be any .

Richard Burns

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The cable is not a standard telephone cable, they are usually laid up in pairs, so it has been used outside of its normal area, therefore any core could have been used for the telephone service.
Your best bet would be to find the other end of the cable and see which cores have been used to connect to the telephone system and use those for your connection.
Checking voltage to find the 0V and -50V might be a bit random if any cores have been cross connected or used for other purposes at the opposite end.


Regular EF Member
That is a very odd cable, appears to be no tracer marks on one of each of the colours. Is there a second green wire and a second black wire we can't see in the picture. I.E. it's an "8 pair" cable, two of each colour?

Both the blues ought to be the first pair, but it's up to whoever installed it to choose which pair they were going to use. As said, the pairs don't seem twisted, so look forward to crappy broadband speed! The order of the colour code for the pairs is...

Slate (Grey, it's known as slate though)


Regular EF Member
Everything up to and including the master socket is the property of Open Reach and you are not allowed to touch it.


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Regular EF Member
This looks to be a 20pair solid colour cable. It will be used for major telephone installations. Unlike modern twin coloured paired cables, the installer creates circuits using different combinations of paired cables, e.g. red with white, red with green, etc, etc. This gives a considerable number of possibly circuit combinations. I doubt they will be good for broadband. Depending on how/what you are wiring, you need either a 2 pair or a four pair cable. Colours do not matter except that the ones used for the telephone line (connected to A and B) need to be the same ones used for the telephone in the socket. The ADSL/VDSL colours also do not matter as long as again they are matched into the correct terminal at each end.

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