RJ connectors

How to punch down Ethernet cables with Rj45 socket

RJ connectors

When the RJ connectors first came into use, they were primarily used for telephones. The great advances in technology created a need for another size connector and the RJ-45 was adapted to fit.

The most common twisted-pair connector is an 8-position, 8-contact (8P8C) modular plug. It is referred to as an RJ45 connector. 


There are two different RJ-45 connector types available:

  1. for Cat 5e cable
  2. for Cat 6 cable

What are the T568A and T568B standards?

The EIA/TIA 568A and 568B standards are best known for two tables T568A and T568B, which describe the connection of twisted pair cable conductors with 8P8C connector pins when organizing an Ethernet network. T568A and T568B are the two color codes used for wiring RJ45 modular plugs.

The only difference between T568A and T568B is the position of the orange and green wire pairs.


The T568A wiring scheme provides backward compatibility for both one pair and two pairs of USOC wiring schemes. It is the preferred wiring pattern. The U.S. Government requires the use of the T568A wiring standard under federal contracts. But the T568B standard is more popular with users, especially for a new network. T568A and T568B are not combined or interchanged.


Network cables consist of four pairs of wires, each of which consists of a solid colored wire and a strip of the same color.

How to punch down the wires?

Network cable consists of 4 twisted pairs, so 8 wires in total. Cat6 cable usually also has a loose plastic core running down the centre, to reduce crosstalk between those 4 twisted pairs. Each pair is colour-coded ,with one of the pair being a solid colour and the other ones are half coloured.

Strip off about a 3cm length of the outer jacket, being careful not to damage the conductors inside. Snip off the plastic crosstalk separator and the ripcord thread that both run along inside the cable. Then untwist all 4 pairs of wires, and pinch each wire tightly between your thumb and forefinger and run along to straighten them all out as best you can.

There are 2 main standards, T-568A and T-568B(Like NEXUS Cat6 Cables) – the only difference is the greens and the oranges trade places. The key importance is that the wiring is the same on both ends of the cable, so if you’re just making a length of cable for yourself at home and terminating both ends with an RJ45 plug then it really doesn’t make any difference – as long as you use the same both end. But it’s better tend to use T-568B because it’s the most widely used. So that’s orange and white, solid orange, green and white, solid blue, blue and white, solid green, brown and white, solid brown.

If you’re adding cabling to an existing setup, or replacing a faulty end, then make sure you use whatever standard is already in use at the location, to make things easier for yourself and any other engineers who might do work there after you.

So, arrange them in the right order and again, run your fingers along to help straighten them out even more so that they sit right and in the correct position. You may find it helpful at this point to take my wire cutters and gently grip the cables – but don’t snip them just yet – and to bunch the ends right up to each other and double check the colours are still in the correct order. Then, holding the base of the wires firmly with your thumb, snip a short length from the end so that we have a really neat, tight bunch at the end. 

Next, take an end plug.So once you’ve cut a short length from the end, carefully slide the arranged wires into the plug and allow them to “pass through” it, hence the name, keeping going until the outer jacket is fully inside as far as it will go. Then, examine the 8 wires and check again that all 8 are still in the correct order. If you accidentally loosened your grip too soon whilst putting the end on, and any cables got in the wrong order for example, you can of course just slide it off, correct, and reinsert without having to start again, waste a plug and make the cable a bit shorter again.

So you are all done and you can connect both end to your connection plug.

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