A Cat 6 wiring diagram maps the eight wires inside the cable to the eight pins of an RJ45 connector, following one of two color codes: T568A or T568B. Both are defined by the same standard, both perform identically, and the only firm rule is to use the same one on both ends of every cable.
This guide gives you the full Cat 6 wiring diagram for both standards, the color code for each pin, how Power over Ethernet uses the pairs, and a step-by-step way to terminate a Cat 6 cable that passes a test the first time.
Key Takeaways
- A Cat 6 wiring diagram follows one of two color-code standards, T568A or T568B. Both are defined by ANSI/TIA-568, and both work. The rule that matters is using the same standard on both ends.
- T568B is the most widely used color code in US commercial installations, while the standard itself recommends T568A. Pick one and stay consistent across the building.
- The color code is the same across Cat 5e, Cat 6, and Cat 6a. Only the cable construction changes, so one Cat 6 cable diagram covers all three.
- A Cat 6 cable has eight wires in four twisted pairs, terminated in an RJ45 connector. Gigabit and faster links use all four pairs at once.
- Cat 6 runs fail at the termination, not the diagram. Untwisting the pairs too far, mixing standards end to end, or using a lower-rated jack are the usual causes.
Have a network installation project?
Cat 6 Wiring Diagram: T568A and T568B Pinouts
A Cat 6 wiring diagram assigns each of the cable’s eight wires to a numbered pin on the RJ45 connector, in either T568A or T568B order. Both pinouts are defined in the ANSI/TIA-568 wiring standard, and a cable wired correctly in either one carries the same signal at the same speed.
T568B color code (pin 1 to pin 8):
| Pin | Wire color | Pair |
|---|---|---|
| 1 | White/Orange | 2 |
| 2 | Orange | 2 |
| 3 | White/Green | 3 |
| 4 | Blue | 1 |
| 5 | White/Blue | 1 |
| 6 | Green | 3 |
| 7 | White/Brown | 4 |
| 8 | Brown | 4 |
T568A color code (pin 1 to pin 8):
| Pin | Wire color | Pair |
|---|---|---|
| 1 | White/Green | 3 |
| 2 | Green | 3 |
| 3 | White/Orange | 2 |
| 4 | Blue | 1 |
| 5 | White/Blue | 1 |
| 6 | Orange | 2 |
| 7 | White/Brown | 4 |
| 8 | Brown | 4 |
The only difference between the two is that the orange and green pairs trade places. Per ANSI/TIA-568, “the difference between the T568A and T568B pinouts is that pairs 2 and 3 (orange and green) are exchanged.” The blue pair stays on pins 4 and 5 and the brown pair on pins 7 and 8 in both diagrams.
This same color code applies to Cat 5e and Cat 6a as well as Cat 6. The wire colors and pin order do not change between categories, so a Cat 6 cable diagram and a Cat 6a cable diagram look identical. What changes is the copper and shielding inside the cable, not the pinout.
T568A vs T568B: Which Should You Use?
Use T568B for most commercial and new US installations, or T568A to match an existing T568A building or a government specification. Both perform the same, so the choice matters less than staying consistent.
ANSI/TIA-568 formally recommends T568A for horizontal cabling, but T568B remains the most widely used color code in US commercial work. The single rule that protects a network is consistency: wire every jack, patch panel, and cable end in a building to the same standard, and match whatever is already installed if you are extending an existing run.
For a wall plate or keystone jack, the answer is the same as for a plug. Punch every jack in the run to one standard, usually T568B in a commercial building, and use that same standard at the patch panel on the other end. Mixing T568A on one end and T568B on the other by accident creates a crossover cable, which modern equipment does not expect on a standard link. Our full T568A vs T568B comparison breaks down the two side by side.
Straight-Through vs Crossover Cat 6 Cables
A straight-through Cat 6 cable uses the same standard, T568A or T568B, on both ends, and connects a device to a switch, router, or wall jack. Straight-through is the normal wiring for a building’s data runs.
A crossover cable uses T568A on one end and T568B on the other, and was once needed to connect two similar devices directly, such as two computers or two switches. That requirement is now gone on current hardware. Automatic MDI-X, per the medium-dependent interface standard, “automatically detects the required configuration, MDI or MDI-X, eliminating the need for crossover cables.” The same standard notes that gigabit and faster links use all four cable pairs at once, so the switch sorts out transmit and receive on its own. For Cat 6 work today, wire straight-through and let the equipment handle the rest.
Power over Ethernet (PoE) Over Cat 6 Wiring
Power over Ethernet sends both data and electrical power over the same Cat 6 cable, so a device such as an IP camera or wireless access point needs only one cable run instead of a separate power circuit. The wiring diagram does not change for PoE. The same eight wires carry the power.
PoE is defined in the IEEE 802.3 standards, and the amount of power depends on the version, per the Power over Ethernet specification:
- 802.3af (PoE): up to 15.4 W supplied, with about 12.95 W guaranteed at the device.
- 802.3at (PoE+): up to 30 W at the port.
- 802.3bt (PoE++): up to 60 W or 90 W, using all four pairs.
Power sources supply between 44 and 57 volts DC. Cat 6 handles PoE well because its conductors are thicker than older cable, which keeps heat and voltage drop in check on long runs. Common PoE devices on a commercial Cat 6 network include IP security cameras, wireless access points, and VoIP desk phones.
How to Wire and Terminate a Cat 6 Cable
Terminating a Cat 6 cable means arranging the eight wires in the chosen color code and crimping them into an RJ45 connector. Cat 6 and Cat 6a both use a standard RJ45, formally called an 8P8C connector, rated for the category. A higher category uses a higher-rated version of the same plug or jack, not a different connector.
You will need a jacket stripper, a crimping tool, RJ45 plugs or keystone jacks rated for Cat 6, a punch-down tool for jacks and patch panels, and a cable tester.
- Strip about 1 to 1.5 inches of the outer jacket, taking care not to nick the wires underneath.
- Separate the four pairs and untwist each pair only as far back as the plug, no more than half an inch.
- Arrange the wires in T568B order from left to right: white/orange, orange, white/green, blue, white/blue, green, white/brown, brown.
- Hold the wires flat and trim them straight so all eight ends are even.
- Slide the wires into the RJ45 plug in order until each one reaches the front of the connector.
- Crimp with the tool until it clicks and the jacket is held firmly inside the plug.
- Repeat on the other end using the exact same standard.
- Test every pin with a cable tester before you close the wall or rack.
For jacks and patch panels, the same color code applies. Punch each wire into the matching slot on the keystone jack, following the T568A or T568B labels printed on the jack. Our guide to RJ45 termination walks through the connector in more detail.
Have a network installation project?
Common Cat 6 Wiring Mistakes
In practice, Cat 6 problems trace back to the termination rather than the diagram. These are the errors that fail a cable test or slow a network down.
- Untwisting the pairs too far. The twist is what cancels interference. Untwist more than half an inch and the run can fail its certification, especially at Cat 6 speeds.
- Mixing standards end to end. T568A on one end and T568B on the other turns a straight-through cable into a crossover by accident. Use one standard for the whole building.
- Using a lower-rated jack or plug. A Cat 6 cable punched onto a Cat 5e-rated jack performs at Cat 5e. The whole run is only as good as its lowest-rated part.
- Ignoring bend radius. Sharp bends and kinks change the cable’s geometry and hurt performance. Keep bends gentle.
- Skipping the test. A miswired or split pair can still link at a lower speed, so it passes a quick look but fails under load. Test every run with a proper tester.
Cat 6 vs Cat 6a: Do You Need to Upgrade?
Cat 6 supports 1 Gbps up to 100 meters and 10 Gbps up to about 55 meters, at a bandwidth of 250 MHz, per the Category 6 cable specification. Cat 6a extends 10 Gbps to the full 100 meters at 500 MHz. The wiring diagram and color code are the same for both, so nothing above changes if you move up a category.
Cat 7 is rated to 600 MHz and also supports 10 Gbps, and is not recognized as a category by the TIA, according to the Category 7 cable reference. For most commercial networks the real decision is Cat 6 versus Cat 6a. Our Cat 6a vs Cat 6 comparison and Cat 6a wiring guide cover that choice in full.
When to Bring in a Commercial Cabling Contractor
For a handful of jacks, terminating your own Cat 6 is manageable with the right tools and a tester. For a full building, a data center, or any run that has to be certified for warranty, the labor, testing, and documentation add up quickly, and a single miswired drop can be hard to find behind a wall.
The Network Installers designs, terminates, and certifies structured cabling for commercial and government facilities nationwide. We have installed Cat 5e and Cat 6 copper, terminations, and patch panels across more than 850 organizations and 1,900 signed projects, and our work is BICSI certified and licensed under C7 #1039579. If you are planning a network cabling project, you can get a free quote or read more about our data cable installation and ethernet cable installation services.
Frequently Asked Questions
Do you use A or B for Cat 6?
Either one works for Cat 6. Most US commercial installations use T568B, while ANSI/TIA-568 recommends T568A. The important rule is to use the same standard on both ends of every cable and match whatever the building already uses.
What is the most common Cat 6 wiring?
T568B is the most common Cat 6 wiring color code in US commercial and new-construction work. T568A is common in residential and government installations and is the standard’s formal recommendation, so both appear in the field.
What order do Cat 6 wires go?
In T568B order, the wires run white/orange, orange, white/green, blue, white/blue, green, white/brown, brown, from pin 1 to pin 8. In T568A, the orange and green pairs swap places while blue and brown stay put.
Should I use T568A or T568B?
Use T568B for most commercial and new US installations, or T568A to match an existing T568A building or a government specification. Both perform identically, so consistency across the site matters more than the choice itself.
Does a Cat 6 cable use all eight wires?
Yes. A Cat 6 cable has eight wires in four twisted pairs, and gigabit and 10-gigabit connections use all four pairs at once. Older 10/100 links used only two of the pairs.
Conclusion
A Cat 6 wiring diagram comes down to two color codes, T568A and T568B, terminated cleanly and identically on both ends. Get the pinout right, keep the untwist short, match the jack rating to the cable, and test every run, and a Cat 6 network will hold its speed for years. The diagram is the easy part. The termination is where reliability is won or lost.
The Network Installers designs and certifies commercial Cat 6 and structured cabling nationwide, and clean, tested terminations are what keep those networks dependable at scale. If you want a Cat 6 installation planned, run, and certified for you, talk to our team.
Have a network installation project?
