Network Cable Color Code: RJ45 Pinout and Wiring Guide

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The RJ45 network cable color code uses either the T568A or T568B wiring standard. For a normal straight-through Ethernet cable, use the same standard at both ends: T568A-to-T568A or T568B-to-T568B. T568B is common for patch cables, while T568A remains an accepted structured-cabling standard.

The key to an accurate RJ45 pinout is viewing the plug from the correct side. With the gold contacts facing the viewer and pin 1 on the left, the conductors must appear in the exact order shown below.

RJ45 Network Cable Color Code: T568A and T568B

T568A: pin 1 through pin 8, conductor colors, and pair roles

Read the plug from the contact side, left to right. The T568A RJ45 color order is:

  • 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

In T568A, the green pair occupies pins 1 and 2, the orange pair occupies pins 3 and 6, the blue pair occupies pins 4 and 5, and the brown pair occupies pins 7 and 8.

T568B: pin 1 through pin 8, conductor colors, and pair roles

T568B keeps the blue and brown pairs in the same positions but swaps the green and orange pairs. Its pin order is:

  • 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

In T568B, the orange pair is on pins 1 and 2, the green pair is on pins 3 and 6, the blue pair is on pins 4 and 5, and the brown pair is on pins 7 and 8.

How the four Ethernet pairs carry signals

Each solid-colored conductor is twisted with its matching white-striped conductor. The pair positions are:

  • Green pair: pins 1 and 2 in T568A, or pins 3 and 6 in T568B
  • Orange pair: pins 3 and 6 in T568A, or pins 1 and 2 in T568B
  • Blue pair: pins 4 and 5 in both standards
  • Brown pair: pins 7 and 8 in both standards

10BASE-T and 100BASE-TX Ethernet use the green and orange pairs for data, while the blue and brown pairs do not carry 10/100 data. 1000BASE-T Gigabit Ethernet uses all four pairs. Power over Ethernet can also use pairs that do not carry 10/100 data, depending on the power-delivery method.

How to Hold an RJ45 Plug and Read the Pinout

Contact-side view: identify pins 1 through 8

The contact-side view is the standard reference for an RJ45 pinout. Hold the transparent plug with:

  • The eight gold contacts facing toward the viewer
  • The locking clip on the opposite side, pointing away or downward
  • The cable entering from behind the plug

In this position, pin 1 is the contact on the far left and pin 8 is the contact on the far right. Read the conductor colors from left to right as pins 1, 2, 3, 4, 5, 6, 7, and 8. The wire order must match the selected T568A or T568B list before crimping.

The plug’s contacts are numbered by their physical positions, not by the colors printed on the cable jacket. A white-striped conductor counts as a separate conductor and must be placed in its own assigned pin.

Clip-side and cable-entry views: why the order appears reversed

Turning the plug over so the locking clip faces the viewer creates a mirror image of the contact-side view. From left to right, the same eight positions will appear as pins 8 through 1, not pins 1 through 8.

Looking into the rear cable-entry side can create the same reversal. The cable-entry view is from the opposite direction from the contact-side view, so the apparent left-to-right color order is mirrored. The pinout has not changed; only the viewing direction has changed.

When checking a finished plug, use one consistent reference: contacts facing the viewer, pin 1 on the left. Comparing one plug from the contact side and the other from the clip side can make a correctly wired cable appear incorrect.

Choose Straight-Through or Crossover RJ45 Wiring

Use the same wiring standard on both ends for a straight-through cable

A straight-through cable has the same standard at both ends:

  • T568A straight-through: T568A on end 1 and T568A on end 2
  • T568B straight-through: T568B on end 1 and T568B on end 2

The pin numbers therefore connect directly: pin 1 connects to pin 1, pin 2 to pin 2, and so on. This is the normal choice for connecting a computer to a switch, a router to a switch, or a patch panel to network equipment.

Choose one standard before terminating the first end, then use that same standard at the other end. Mixing standards accidentally can swap the green and orange pairs and produce a crossover cable instead of a straight-through cable.

Use T568A on one end and T568B on the other for a crossover cable

A crossover cable uses T568A on one end and T568B on the other. This swaps the green and orange pairs:

  • Pin 1 connects to pin 3
  • Pin 2 connects to pin 6
  • Pin 3 connects to pin 1
  • Pin 6 connects to pin 2
  • Pins 4 and 5 remain within the blue pair
  • Pins 7 and 8 remain within the brown pair

Crossover cables were traditionally used to connect similar equipment directly, such as a computer to a computer or a switch to a switch. Most modern Ethernet ports support auto MDI-X and can correct for the transmit and receive pair arrangement automatically, so a crossover cable is rarely required. It remains useful for older equipment, specialized links, and troubleshooting.

How to Terminate and Test the Ethernet Cable

Prepare the pairs while limiting untwist at the plug

  1. Cut the cable cleanly and select a modular plug that matches the cable category and conductor type. Solid-core and stranded cables commonly require different plug designs.
  2. Strip only enough outer jacket to arrange the conductors and place the jacket inside the plug’s strain-relief area. Avoid damaging the insulation on the individual wires.
  3. Separate the four twisted pairs, then arrange the conductors in the selected T568A or T568B order. Keep each pair twisted as close to the plug as practical. For typical Category 5e and higher terminations, limit untwisting to approximately 13 mm, or one-half inch, where possible.
  4. Flatten the conductors without changing their order. Trim the ends evenly so all eight wires reach the front of the plug together.
  5. Insert the conductors with the contacts facing up in the chosen reference position. Look through the transparent plug to confirm that every wire reaches its corresponding front channel and that the outer jacket extends under the rear strain relief.
  6. Crimp the plug with a compatible eight-position, eight-contact modular crimp tool. The contacts should press into the individual conductors, while the rear strain relief should grip the cable jacket rather than the loose wires.

Inspect the crimp and run a wire-map test

Inspect the plug from the contact side before connecting it to equipment. The eight colors should be in the intended order, no conductor should be missing or doubled, and all conductors should extend to the same front position. The jacket should be inside the plug body, and the strain-relief tab should hold the jacket securely. A large gap between the jacket and the plug often indicates inadequate strain relief.

Connect both ends to a wire-map tester. For a straight-through cable, the expected result is a direct 1-to-1 map from pins 1 through 8. For a crossover cable, the tester should show the intentional 1-to-3, 2-to-6, 3-to-1, and 6-to-2 changes, with the blue and brown pair positions remaining correctly paired.

A proper wire-map test can identify open conductors, short circuits, reversed conductors, crossed pairs, and split pairs. A split pair can pass a basic continuity check while placing conductors from different twists together, so a pair-aware wire-map tester is preferable. If the cable passes the map but fails at its rated speed, use a suitable certification or performance tester to check insertion loss, return loss, and crosstalk.