Ethernet RJ45 Color Code with Pinout (T568A, T568B)

Last updated on March 21st, 2024 at 05:20 pm

An Ethernet cable consists of 8 wires (or 4 pairs of wires). These cables follow a specific color code with respect to the arrangement of the wires. The connector of ethernet cable is available in two standards, i.e., T568A and T568B.

And based on the combination of these two connectors(used at the ends of an ethernet cable), two widely used ethernet cables are made, i.e., Straight and Crossover. RJ45 color code and pinout of each configuration are given below.

Ethernet RJ45 cables

An Ethernet cable is available in many types. Straight-through, Crossover, Rolled, Loopback and T1 are some of them. Among these straight-through and crossover are the commonly used wiring standards. The other standards are reserved for specific network applications.

High quality Ethernet cable

High-Quality Ethernet cable(50 ft)

These cables(connector) follow two pinout standards: T568A and T568B. Both standards are similar in their electrical properties. The selection of these standards purely depends on the organization and the country. Both standards give the same performance.

RJ45 cable pinout with color code

The connector of Ethernet cable has two standards, i.e., T568A and T568B. Both these standards have the same number and color of wires. The only difference lies in the positions of green and orange wires. Let’s discuss T568A and T568B pinout standards in detail.

RJ45 (T-568A) color code and pinout

Pinout of T-568A Standard
Pinout of T-568A standard

T568A pinout standard was commonly used in the ’90s. It’s still in use but T568B is more common now. The key highlight of T568A wiring is that it is backward compatible with one-pair as well as two-pair USOC (Universal Service Ordering Code) wiring schemes.

The pinout description with the color code of T568A is given in the table below.

PinWire colorSignalSignal description
1White/GreenTX1+Transmit +
2GreenTX1-Transmit –
3White/OrangeRX+Receive +
4BlueTX2+Bi-Directional Transmit +
5White/BlueTX2-Bi-Directional Transmit –
6OrangeRX-Receive –
7White/BrownTX3+Bi-Directional Transmit +
8BrownTX3-Bi-Directional Transmit –
Pinout and color code of T568A

RJ45 (T-568B) color code and pinout

Pinout of T-568B Standard
Pinout of T-568B standard

T568B standard is a widely used wiring standard in current Ethernet applications as it gives better protection from noise. It also isolates the signal more effectively as compared to T568A. It is backward compatible with only a one-pair USOC wiring scheme.

The pinout description with the color code of T568B is given in the table below.

PinWire colorSignalSignal description
1White/orangeTX1+Transmit +
2OrangeTX1-Transmit –
3White/GreenRX+Receive +
4BlueTX2+Bi-Directional Transmit +
5White/BlueTX2-Bi-Directional Transmit –
6GreenRX-Receive –
7White/BrownTX3+Bi-Directional Transmit +
8BrownTX3-Bi-Directional Transmit –
Pinout and color code of T568B

Types of Ethernet cable

As already mentioned above, the connector comes in two standards, T568A and T568B. A cable may have the same or different standard connector at its end. Based on this, there are two types of cables, Straight and Crossover.

50 ethernet cable

Best deal on Ethernet cable(50 ft)

Straight-through cables

The straight-through cables use the same connector standard at both ends. This means that both ends either have T568A or T568B standard connectors. The figure below shows the two ends of a cable connected with the T568A standard.

Straight cable pinout
Straight cable pinout

The straight-through cables are used to connect dissimilar devices. For example, a hub connected to a laptop. Also, the connection of Data Terminating Equipment (DTE) to Data Communications Equipment (DCE) is usually done using straight-through cables.

Crossover cables

When the ethernet wires are terminated with T568A standard at one end and with T568B standard at the other end, they are called crossover cables. It follows the reverse features of straight-through cables. They are used to connect similar devices. Like a laptop to another laptop.

Crossover cable pinout
Crossover cable pinout

The figure above shows that the 4 pairs of wires are cross-connected in this case. Whereas, in straight-through cables, the wires are connected straight to the other end.


What is RJ45 A and B?

The A and B in RJ45 denote the pinout standards, these are T568A and T568B.

Why is it called RJ45?

The term “RJ45” stands for “Registered Jack 45.” It refers to a standard type of connector commonly used for Ethernet networking cables. The “45” indicates that it is the 45th iteration of the Registered Jack standard, which was developed by the Federal Communications Commission (FCC) in the United States.

What does Cat 5 stand for?

“Cat 5” stands for Category 5. It’s a designation used for a type of twisted pair cable commonly used in Ethernet networking.

Photo of author

Kanishk Godiyal

I have a keen passion for learning and understanding various concepts of electronics. Combining my knowledge with my SEO skills, my aim is to make electronics easy for every tech enthusiast out there.

Leave a Comment