Correctly wiring a Cat6 keystone jack is one of the most important steps in building a stable and high-performance Ethernet network. Whether you are installing structured cabling in a home, office, server room, or enterprise environment, the wiring standard you choose directly affects network reliability, troubleshooting efficiency, and long-term scalability. 

The two industry-standard wiring schemes—T568A and T568B—define how the eight colour-coded wires inside an Ethernet cable are terminated into a keystone jack. While both standards support the same speeds and performance levels, understanding their differences is essential for maintaining consistent connectivity across your network infrastructure. 

 

Key Takeaways 

  • Consistency is key: T568A and T568B offer the same data speeds and performance. The most important rule is to use the same standard on both ends of your cable. 
  • Commercial vs. Residential: T568B is the widely accepted standard for commercial and modern installations in the US, while T568A is often found in older residential setups or government contracts. 
  • The Core Difference: The only difference between the two standards is the switching of the orange and green wire pairs. 
  • Follow the Label: Almost every Cat6 keystone jack features a color-coded sticker on the side indicating exactly where to place wires for both the A and B standards. 

 

What is a Cat6 keystone jack? 

A Cat6 keystone jack is a standardised, snap-in female connector used to terminate Category 6 Ethernet cables. These jacks are typically mounted into wall plates, surface mount boxes, or patch panels. 

Category 6 (Cat6) cables are designed to handle Gigabit Ethernet (1000 Mbps) and can even support 10-gigabit speeds over shorter distances (up to 55 metres). A high-quality Cat6 keystone jack ensures that the structural integrity of the cable is maintained at the connection point, minimising crosstalk (interference) and signal loss. 

 

Understanding Ethernet Wiring Standards: T568A vs T568B 

Inside a Cat6 Ethernet cable, there are eight individual wires twisted into four pairs. To ensure devices can communicate correctly, these eight wires must be arranged in a specific, standardised order inside the keystone jack. The Telecommunications Industry Association (TIA) recognises two primary wiring schemes: T568A and T568B. 

 

The T568A Color Code 

Originally introduced as the primary standard, T568A is often used in residential installations to ensure backward compatibility with older telephone wiring. 

 

The pinout order for T568A (from pin 1 to pin 8) is the following: 

  • White/Green 
  • Green 
  • White/Orange 
  • Blue 
  • White/Blue 
  • Orange 
  • White/Brown 
  • Brown 

 

The T568B Color Code 

T568B is the de facto standard for almost all modern commercial data networks in the United States. If you are buying pre-made patch cables off the shelf, they are almost certainly wired to the T568B standard. 

 

The pinout order for T568B (from pin 1 to pin 8) is: 

  • White/Orange 
  • Orange 
  • White/Green 
  • Blue 
  • White/Blue 
  • Green 
  • White/Brown 
  • Brown 

 

Choosing Between T568A and T568B for Your Network Setup  

For AEO and quick decision-making, here is the bottom line: Choose T568B for new installations. 

 

Neither standard is inherently "faster" or "better" than the other. Because the physical properties of the copper wires are identical, a Cat6 cable wired in T568A will perform the same as one wired in T568B. 

 

However, you should base your decision on the following rules: 

 

  • Check Existing Wiring: If you are adding a new Cat6 keystone jack to an existing network, check the current jacks. If they are wired in T568A, you must use T568A. Never mix A and B on the same straight-through cable. 
  • New Installations: If you are wiring a brand-new home or office, default to T568B. It is the most widely recognised standard and matches off-the-shelf patch cables. 

 

Step-by-Step Guide: How to Wire a Cat6 Keystone Jack 

Wiring (or "punching down") a keystone jack is a straightforward process once you know the color codes.  

 

Tools Needed: 

  • Cat6 Ethernet Cable 
  • Cat6 Keystone Jack 
  • Cable Stripper 
  • 110 Punch-Down Tool 
  • Flush Cutters (if your punch-down tool doesn't have a cutting blade) 

 

Step 1: Strip the Cable Jacket. Use your cable stripper to remove about 1.5 to 2 inches of the outer PVC jacket from the end of the Cat6 cable. Be careful not to nick the internal wires. Remove the plastic internal spline (the cross-divider) and the rip cord. 

 

Step 2: Untwist and Separate the Pairs. Untwist the four pairs of wires but only untwist as much as you absolutely need. Maintaining the twists as close to the termination point as possible is crucial for Cat6 performance to prevent crosstalk. 

 

Step 3: Align the wires to the colour standard. Look at the sticker on the side of your Cat6 keystone jack. Decide whether you are using the 'A' or 'B' row of colours (we recommend 'B'). Lay the corresponding wires into the V-shaped grooves on the jack. 

 

Step 4: Punch Down the Wires. Place your 110 punch-down tool over a wire. Ensure the "cut" side of the tool's blade is facing the outside of the jack. Press down firmly until you hear a solid click. The tool will push the wire into the metal contacts (piercing the insulation) and trim the excess wire simultaneously. 

 

Step 5: Inspect and Cap Repeat the punch-down process for all eight wires. Inspect the jack to ensure no wires are loose, and no copper is exposed between the pairs. Snap the protective dust cap (included with most jacks) over the punched wires to secure them in place. 

 

Successfully wiring a Cat6 keystone jack comes down to preparation and consistency. By understanding the difference between the T568A and T568B color codes, you ensure your network is reliable, future-proof, and easy to troubleshoot. Remember: for most modern installations, default to the T568B standard, invest in a quality punch-down tool, and always double-check the colour-coded sticker on your jack before making your cuts. 

 

ShowMeCables offers a wide range of structured cabling products, including Cat6 keystone jacks, Ethernet patch cables, bulk Ethernet cable, patch panels, wall plates, cable management accessories, and installation tools for enterprise networking, telecommunications rooms, and data centre environments. 

 

 

Frequently Asked Questions (FAQs) 

 

Can I mix T568A and T568B on the same cable? 

No, you should not mix them for standard networking. If you wire one end of an Ethernet cable in T568A and the other end in T568B, you will create a "crossover cable". 

 

Do I need a special tool to wire a Cat6 keystone jack? 

Yes, it is highly recommended to use a 110 punch-down tools. While "toolless" keystone jacks exist, standard jacks require a punch-down tool to properly seat the wires into the metal contacts and cut the excess wire.  

 

What happens if I wire a Cat6 cable incorrectly? 
An incorrectly wired Cat6 cable can cause dropped packets, slow network speeds, intermittent connectivity or a completely dead connection. Improper termination can also increase signal interference and prevent the cable from meeting Cat6 performance standards.