Splitting a CAT5e into Ethernet + Telephony

June 16, 2011 by Andrew Seymour

So, we recently got another landline into the house thanks to BT Infinity so obviously they make it so you can’t take out an Infinity package without also inclusively bundling an unlimited talk plan – seems like a waste not to use it. Problem is, it’d be best if the second line was in the “office” upstairs, it’d cost £100 from the BT Engineer to do this which is a small fortune considering what he has to do – so, we already have an CAT5e cable running into the opposite room that doesn’t get used much, so, why not just split it.


That’s the socket downstairs, at the moment, there’s 2 ethernet cables connected to it and 1 RJ11 for Telephone (it’s connected like that to test that it works upstairs) – that’s the one we’ll be splitting – on the second picture it translates into the 2nd etherent cable coming in. First, we need to remove the Brown + Green pairs.


So, once that’s done – that’ll still work but we now need to stretch that over to socket number 4 on the quad ethernet panel. On top of that, we now need to make the Green Pairs = Blue and Brown = Orange.


So now, although it may look a bit of a mess (splitting ethernet cables is never a good thing really, you should always plan ahead and install at least 2 per room bringing it back to a larger switch hidden somewhere, but, that’s all in hindsight now). So, let’s take a look at the ethernet socket on the other side of the office wall.


So, what we need to do is take the casing back from the wire coming from the wall as far as we can go and then push the Brown and Green pairs through to the other side. Oh and put a wall back box on.


So remember at this stage we’re still doing the Green = Blue and Brown = Orange conversion so it converts correctly downstairs – remember, this one is now in the office. Put the face plate on, and connect the telephone. Labels are good too!


Now we need to go back downstairs and put the faceplate back on so it’s all nice and tidy, this should all now work.


That’s it! Now you have a split ethernet cable without the need to install a 2nd to get the same experience, remember though that if you split a gigabit cable then you’re reducing it to 100megabit (that’s a 10x drop) but, if it doesn’t get used or you’re not that bothered about the speed decrease then this is an ideal solution. Overall cost, £10.

Categories: Broadband, Ethernet, Telephony