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 | 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 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 | 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.
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 | 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.