T568B Pinout
T568B is widely used in structured cabling installations. A straight-through patch cable uses T568B on both ends, while a crossover cable uses T568B on one end and T568A on the other.
Pin and Color Sequence
Most Common Straight-Through Standard| Pin | Pair | Wire Color | Function |
|---|---|---|---|
| 1 | Pair 2 | White/Orange | TX+ |
| 2 | Pair 2 | Orange | TX− |
| 3 | Pair 3 | White/Green | RX+ |
| 4 | Pair 1 | Blue | Unused / PoE pair |
| 5 | Pair 1 | White/Blue | Unused / PoE pair |
| 6 | Pair 3 | Green | RX− |
| 7 | Pair 4 | White/Brown | Unused / PoE pair |
| 8 | Pair 4 | Brown | Unused / PoE pair |
Termination note: Hold both plugs in the same orientation and verify the clip position before reading pin order. Keep pair twists as close as practical to the contact termination and follow the applicable cabling standard.
T568A Pinout
T568A swaps the green and orange pairs compared with T568B. A straight-through cable uses T568A on both ends. Mixing the two standards creates a crossover pinout for traditional 10/100 Ethernet equipment.
Pin and Color Sequence
Alternative Structured Cabling Standard| Pin | Pair | Wire Color | Function |
|---|---|---|---|
| 1 | Pair 3 | White/Green | TX+ |
| 2 | Pair 3 | Green | TX− |
| 3 | Pair 2 | White/Orange | RX+ |
| 4 | Pair 1 | Blue | Unused / PoE pair |
| 5 | Pair 1 | White/Blue | Unused / PoE pair |
| 6 | Pair 2 | Orange | RX− |
| 7 | Pair 4 | White/Brown | Unused / PoE pair |
| 8 | Pair 4 | Brown | Unused / PoE pair |
Termination note: Hold both plugs in the same orientation and verify the clip position before reading pin order. Keep pair twists as close as practical to the contact termination and follow the applicable cabling standard.
Crossover Cable
A crossover cable terminates one end as T568A and the other as T568B. Modern Auto-MDI/MDI-X ports often detect and compensate for this automatically, but the wiring pattern remains important for troubleshooting and legacy equipment.
Pin and Color Sequence
T568A ↔ T568B| Pin | Pair | Wire Color | Function |
|---|---|---|---|
| 1 ↔ 3 | Transmit ↔ Receive | Orange/Green pair swap | TX ↔ RX |
| 2 ↔ 6 | Transmit ↔ Receive | Orange/Green pair swap | TX ↔ RX |
| 4 ↔ 4 | Pair 1 | Blue / White-Blue | Straight |
| 5 ↔ 5 | Pair 1 | White-Blue / Blue | Straight |
| 7 ↔ 7 | Pair 4 | White-Brown / Brown | Straight |
| 8 ↔ 8 | Pair 4 | Brown / White-Brown | Straight |
Termination note: Hold both plugs in the same orientation and verify the clip position before reading pin order. Keep pair twists as close as practical to the contact termination and follow the applicable cabling standard.