Difference Between T568A and T568B

Difference Between T568A and T568B

If you’ve worked with RJ45 modular plugs or connectors, then you probably already know about the two most agreed-upon standards, T568A and T568B. What you may not know is the difference between them, and that’s why you’re up on the internet trying to find it out. Well, you’ve come to the right place!

Even though they are almost identical, it will be helpful for you to understand the difference between T568A and T568B. So, we’re going to explore how they are distinct from each other, allowing you to build the perfect network!


Understanding the T568A and T568B

Understanding the T568A and T568B

Before we go any further, we’re going to briefly discuss the T568A and the T568B. What exactly are they?

Simply put, they are wiring standards unanimously agreed by the TIA, EIA, and ANSI. Both of these standards are designed to provide flawless wiring schemes for 8-position RJ45 modular plugs. They help in making the right arrangements for terminating network cables like CAT cables.

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So, What Are the Major Differences?

Now that we understand what T568A and T568B are, we can go right ahead to the point where we address the differences. So, here we go!

Interchanged Pairs

t568a Vs t568b

The pairs in network cables, specifically the CAT cables, are based on four different colors. Now, the main difference between the two standards is due to the change in the color pattern. You see, the orange and the green pairs are swapped or interchanged in the cables. The rest of the pairs remain unchanged.

However, regardless of the difference, both of these standards get the same result. That’s what makes them so confusing!



The T568B is a newer standard that complies with the AT&T 258A color codes. It offers backward compatibility exclusively to one pair of USOC wiring setups.

On the other hand, the T568A is more preferred due to the fact that it’s perfectly compatible with one pair as well as two pair USOC wiring schemes. Moreover, the government only accepts the use of the T568A standard for all sorts of wiring projects managed under federal contracts.


Business & Residential

The T568B is more suitable for business applications as it offers excellent noise isolation and enhanced speed. For an application under a residential setting, the T568A will be preferable.


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Which One Should I Use?

As a rule of thumb, you should never combine or interchange the T568A and T568B. In the US, the T568B is the go-to schematic for new networks. You are free to choose any if you’re building a network from scratch.

It is crucial to find out which wiring schematic was used originally if you want to rebuild or modify an existing network. You should then follow that exact standard.


Final Words

As you can see, the difference between T568A and T568B is quite insignificant. Both of them can be used to serve the same purpose. The T568A is still the more popular choice, but newer projects use T568B. You can feel free to use either one of these standards to build your network.

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