Connections

A network connection only used 2 pairs of wires, and in a CAT5 cable there are 4 pairs!

The wires that are needed are: 1, 2, 3 and 6. I use the following convention:

Connection 1:
Pin 1 – WHITE/Orange
Pin 2 – ORANGE/White
Pin 3 – WHITE/Green
Pin 6 – GREEN/White

Connection 2:
Pin 1 - WHITE/Blue
Pin 2 – BLUE/White
Pin 3 – WHITE/Brown
Pin 6 – BROWN/White

As you can see Connection 1 is the normal way to wire up a connection – Connection 2 simply uses the 2 pairs that are not usually used.

Double Outlet Socket

Here is a photo of a double CAT5 socket with the wires connected:

Double Outlet Plugs:

If you want to crimp plugs on the the cable for a set up like this, then here is how to do it:

Cut the cable, and remove enough of the outer sleave so that the split cable is long enough for you – here I was just connecting these 2 ends in to a switch.

Crimp the cable as above.

A Y-Split CAT5 cable with plugs:

Here is a close-up of the crimped plugs:

Interference / Cross Talk Problems?

Some people say that running a network like this can cause problems with the signals disturbing eachother – do bear this in mind – whilst I’ve not had a problem, I’ve only been using it on short cable lengths. Remember this if you do have problems, and you may need to find other means, eg wireless or Ethernet over Power.

Obviously, where possible stick with one cable per connection and just use this dual cabling setup for emergencies or where you have no other choice.

Notes:

This will tend to only work for computer equipment on an Ethernet Network.  Some things need more than 2 pairs – devices like Video over CAT5 of VGA over CAT5 tend to make use of all 4 pairs – and so they won’t work when split and only using 2 pairs!