What’s the difference between T568A and T568B wiring schemes?

T568A and T568B are the standards specified by ANSI, TIA, and EIA for RJ45 jacks and plugs that refer to the position of the wires inside the eight-position modular plugs.

These two standards are very alike. The only visible difference between them is that pairs 2 and 3 (green and orange) are interchanged.

What’s the similarity between T568A and T568B?

Here’s why

These cables’ pairs consist of four colors (blue, orange, green and brown) and each pair consists of colored wired twisted together with another wire of the same color, striped with white.

When you untwist the four pairs, they result in 8 individual wires one for each connector’s plug.

Nevertheless, though you may think the only difference between T568A and T568B is the swap between the orange and the green cable:

There are a couple of compatibility differences that could affect your decision when choosing an RJ45 scheme for your infrastructure.

You see… T568B is a more up-to-date scheme and is the more widely chosen wiring scheme because it matches AT&T’s 258A color code.

And also, it offers backward compatibility with one-pair USOC wiring schemes..

Now comes the question, can T568A and T568B be mated?

Let's build it up: T568A or T568B?

• When building a residential network, choose T658A wiring scheme.
• If the network project configurations are available, choose the specified wiring scheme.
• Duplicate the wiring scheme that’s already being used when escalating a network.

Wiring Standards