When working with networking equipment, understanding RJ45 Ethernet wiring color guides is essential for ensuring reliable data transmission. Whether setting up a home network, a business infrastructure, or troubleshooting an existing connection, knowing the correct wiring scheme will help you create functional and efficient network cables.
What Is an RJ45 Connector?
An RJ45 connector is an eight-pin modular plug used to connect Ethernet cables to networking devices. These connectors are commonly used in structured cabling systems for transmitting data in LAN (Local Area Network) environments. The proper arrangement of wires inside the connector is crucial for maintaining signal integrity and avoiding connectivity issues.

Wiring Standards: T568A and T568B
There are two primary wiring standards for RJ45 Ethernet cables:
- T568A – This standard is used in government and residential cabling projects in many countries.
- T568B – Commonly found in commercial installations and the most widely used standard worldwide.
Both standards serve the same purpose and can be used interchangeably as long as both ends of the cable follow the same wiring scheme. However, using different standards on each end results in a crossover cable, which is typically used to connect two similar devices directly.
RJ45 Ethernet Cable Color Codes
The color-coded arrangement of wires in an Ethernet cable ensures proper data transmission. Below are the wiring guides for both T568A and T568B standards:
T568A Wiring Scheme:
- Pin 1 – White/Green
- Pin 2 – Green
- Pin 3 – White/Orange
- Pin 4 – Blue
- Pin 5 – White/Blue
- Pin 6 – Orange
- Pin 7 – White/Brown
- Pin 8 – Brown
T568B Wiring Scheme:
- Pin 1 – White/Orange
- Pin 2 – Orange
- Pin 3 – White/Green
- Pin 4 – Blue
- Pin 5 – White/Blue
- Pin 6 – Green
- Pin 7 – White/Brown
- Pin 8 – Brown
The key difference between the two standards is that the positions of the green and orange wire pairs are swapped.

Straight-Through vs. Crossover Cables
Depending on how an Ethernet cable is wired, it can function as a straight-through cable or a crossover cable:
- Straight-Through Cable: Uses the same wiring standard (either T568A or T568B) on both ends. It is typically used to connect different types of devices, such as a computer to a switch or router.
- Crossover Cable: Uses T568A wiring on one end and T568B on the other. This configuration allows two similar devices (e.g., two computers) to communicate directly without the need for a switch.
Choosing the Right Wiring Standard
For most Ethernet installations, T568B is the preferred standard due to its widespread use in business environments. However, if your project adheres to government or residential standards, T568A may be required.
When working on an existing network, it is essential to verify which wiring scheme is already in use. Mixing T568A and T568B in the same network can cause confusion, especially when troubleshooting connectivity issues.
How to Terminate an RJ45 Cable
Properly terminating an Ethernet cable requires attention to detail. Follow these steps to ensure a secure and functional connection:
- Strip about 1 inch (2.5 cm) of the outer jacket from the cable using a cable stripper.
- Untwist the wire pairs and align them according to the chosen wiring standard.
- Trim the wires evenly, leaving about 0.5 inches (1.3 cm) exposed.
- Insert the wires into the RJ45 connector, ensuring each wire reaches the contacts.
- Use an RJ45 crimping tool to secure the connector to the cable.
- Test the cable using a cable tester to ensure proper connectivity.

Conclusion
A solid understanding of RJ45 Ethernet wiring color guides is essential for anyone working with network infrastructure. By following established wiring standards like T568A and T568B, you can ensure compatibility, reliability, and efficient data transmission in your network.
Whether setting up a new network, repairing connections, or creating custom-length cables, adhering to these standards will help you build a robust networking system that meets industry requirements.