Cat6 Pin Diagram: Complete RJ45 Wiring Guide
A Cat6 pin diagram shows exactly which wire connects to which pin inside an RJ45 connector on a Cat6 Ethernet cable. Inside the connector, eight color-coded wires terminate into eight gold contact pins. The order those wires are inserted — the "pinout" — is defined by two standards published by the TIA/EIA: T568A and T568B. They are functionally interchangeable; the only difference is that the orange and green wire pairs trade places on pins 1, 2, 3, and 6. Understanding the Cat6 pin diagram lets you terminate cables correctly, verify existing installations with a tester, and troubleshoot link failures caused by reversed or split pairs.
What Is a Cat6 Pin Diagram?
The eight wires inside a Cat6 cable form four twisted pairs, each with its own color identity. Pair 1 is blue (pins 4 and 5), Pair 2 is orange (pins 3 and 6), Pair 3 is green (pins 1 and 2), and Pair 4 is brown (pins 7 and 8). Notice in the Cat6 pin diagram that the blue pair sits in the middle and the green pair is split — the green wires wrap around the blue pair on pins 3 and 6. This is not random; it preserves the twist lengths that cancel electromagnetic interference, which is why untwisting more than half an inch of wire while terminating degrades link quality.
Cat6 Pin Diagram Color Codes: T568A vs T568B
For a straight-through cable, you use the same standard on both ends. In the T568B Cat6 pin diagram, pin 1 is White/Orange, pin 2 is Orange, pin 3 is White/Green, pin 4 is Blue, pin 5 is White/Blue, pin 6 is Green, pin 7 is White/Brown, and pin 8 is Brown. T568B is the most common in commercial environments and is the de facto default for gigabit Ethernet. T568A swaps the orange and green pairs and is frequently found in residential and government installations because it is backwards-compatible with older two-pair telephone wiring standards (USOC). Whichever you choose, be consistent — mixing standards within the network is the fastest way to create intermittent or no-link connections.
Which Pins Carry Data on a Cat6 Pin Diagram?
At gigabit speeds, all eight wires are used for simultaneous send and receive, so every pin matters. However, the core signaling is carried on the orange and green pairs — pins 1, 2, 3, and 6. This is why older 100BASE-TX networks only need four conductors, and why the blue and brown pairs can be repurposed by Power over Ethernet without disrupting data. In 1000BASE-T, PoE applies DC voltage in a common-mode fashion on top of the data signal, so power and data coexist on the same wires without interference.
Straight-Through vs Crossover Wiring
A crossover cable reverses the transmit and receive pairs so two like devices can talk to each other directly. Historically you needed one to connect a PC to another PC or to cascade switches without uplink ports. With the near-universal adoption of auto-MDIX (automatic medium-dependent interface crossover) in modern switches, routers, and NICs, crossover cables are rarely necessary — the equipment detects the wiring and adjusts internally. If you do make one, wire one end T568B and the other T568A.
How to Crimp Using the Cat6 Pin Diagram
To terminate a cable, strip about an inch of the outer jacket, untwist the pairs, and arrange the wires in the exact pin order shown in the Cat6 pin diagram above. Flatten them into a single row, trim the ends evenly, and push the bundle into the RJ45 plug with the clip facing away from you. The wires should slide all the way until their tips are visible at the front of the plug. Crimp firmly, then always verify with a cable tester — the two most common mistakes are reversed pairs and wires that do not reach the end of the connector, both of which produce confusing intermittent faults. Keep this Cat6 pin diagram handy and check each wire against the table before you crimp.