RJ11 cable colour codes

I have a BT master socket on one side of what was an outside wall with the modem on the other side. The hole through the wall isn’t very big so getting a RJ-11 Plug through is difficult. It looked to be no problem, I cut a plug off one end of a lead managed to use a wire mouse and got it through. Then, s**t the colour of the cables is different to the BT instructions on direct wiring. I have Yellow, Green, Red and Black wired on to the other plug as I have seen on other internet sites. But I can’t fine how they equate to the BT cable colours so would be grateful if someone could let me know how they match up.

For an RJ11 to RJ11 cable, the plugs on both ends of the cable should be the same. Can you not see the wire colours in the plug that you cut off?

Sorry I didn't make my self clearer enough, I want to wire it up direct to the master socket not put a plug back on. The instructions at https://www.openreach.co.uk/orpg/home/helpandsupport... show very different colours to those used on the cable I have. It’s which of these I have are used in place of the colours given by BT to directly wire up there master socket not rewire a plug.

The pins the modem needs are the middle two, 3 and 4. If it’s clear plastic you should be able to see the colours, otherwise you’ll need a meter.

Post deleted by 4M2

Thank you does it matter which ones are used, into the BT conexters?

Centre pins and polarity does not matter

Thank you

Hi John

This https://i.pinimg.com/originals/93/0e/2c/930e2c6da031... should make it clear.

(It also explains why cutting a RJ11 plug off a 4-core phone cable and simply trying to crimp on a BT 431A plug replacement without realigning the 4-core cable into the new plug will fail.)

Cheers!

Make sure that RJ11 is suitable cable type for connecting direct to the master - it may be if the wires are not the right type then it won't make a good connection and could cause you issues with the broadband. Personally I would have got a data extension kit that would have allowed you to put an RJ11 socket where the router is and then plug the standard RJ11 cable into that rather than cutting the end of the cable.

It was a failure, it didn't look as if the conexter cut through the wire covering so back to the drawing board. The "old" screw" conextions were much more forgiving of this diffrences.

I suspected the cable may not be suitable.

Personally I would buy some Cat5e cable and a RJ11 socket. Run the cable from the data connections on the BT socket through the wall and then connected into the back of the RJ11 socket. Then you can plug a standard modem cable into the socket.

EDIT : You should also be able to use a standard RJ45 socket - RJ11 plugs will fit in RJ45 sockets - it may be easier/cheaper for RJ45 than for RJ11.

Edited by ian72 (Wed 05-Aug-20 11:25:48)

In reply to a post by ian72:

I suspected the cable may not be suitable.

Personally I would buy some Cat5e cable and a RJ11 socket. Run the cable from the data connections on the BT socket through the wall and then connected into the back of the RJ11 socket. Then you can plug a standard modem cable into the socket.

EDIT : You should also be able to use a standard RJ45 socket - RJ11 plugs will fit in RJ45 sockets - it may be easier/cheaper for RJ45 than for RJ11.

And the OP should make sure it is INFRASTRUCTURE Cat5e with solid conductors rather than multi-strand.

After the cable I tried failed to work in the BT conexter I am worried I may have the same problem with Cat5 as well

As another poster said as long as you use infrastructure cabling it should be fine - the RJ11 lead will not have suitable cable types for connecting.

Cat5e SOLID will be fine, you can get four pair or two pair, either will be suitable.

Cat5e 24 AWG has a conductor diameter of 0.5104 and BT internal CW1308 is 0.50 (nominal).

CAT5 cable will be fine.

Only thing to watch is that it is like some Telephone cable that I have come across which was on a drum marked "CCS" turned out to be Copper Covered Steel. Not good. Test with a magnet, proper CAT5 being copper will not be attracted by a magnet.

BT would use CW1308 cable. https://www.ebay.co.uk/itm/5M-WHITE-TELEPHONE-CABLE-... This seller is offering copper cable, but a quick search produced CCS which is not so good.

My advise to get a connection through a wall, is to use a RJ11 socket. Something like:
https://www.ebay.co.uk/itm/RJ11-TELEPHONE-SOCKET-MOD...

And a RJ to RJ cable of whatever length you need between that new socket and the MODEM.

Cheers!