What is 568B and 568A?

Overview

568A and 568B are two wiring standards used for terminating Ethernet cables, specifically twisted-pair cables like Cat5e, Cat6, and Cat6a. These standards define the order of the colored wires inside the cable and ensure consistent, reliable network connections. Understanding the difference between 568A and 568B is essential for anyone working with structured cabling or setting up Ethernet networks.

Key Features

• Wiring Standards
  • Both 568A and 568B define the pinout configuration for RJ45 connectors
  • Each standard arranges the eight wires in a specific color-coded sequence
• Color Code Differences
  • 568A: Green pair comes first
    • 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
  • 568B: Orange pair comes first
    • 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
• Compatibility
  • Both standards are functionally equivalent for most Ethernet applications
  • Mixing 568A and 568B on opposite ends of a cable creates a crossover cable, used for direct device-to-device connections
• Industry Usage
  • 568B is more commonly used in commercial installations in the U.S.
  • 568A is often preferred in government and residential installations

Benefits to Consumers

• Ensures consistent and reliable Ethernet connections
• Simplifies DIY cable termination with clear color coding
• Enables creation of crossover cables for direct device links

Benefits to Businesses

• Supports structured cabling systems for scalable network infrastructure
• Reduces installation errors and improves troubleshooting
• Complies with industry standards for professional-grade networking

Availability

RJ45 connectors, punchdown tools, and wiring diagrams for both 568A and 568B are widely available through networking hardware suppliers. Most patch panels and keystone jacks support both standards.

Conclusion

568A and 568B are foundational wiring standards for Ethernet cabling. Choosing the right one—and using it consistently—ensures reliable network performance and simplifies installation across residential and commercial environments.