Twisted-Pair Cable and Pin Assignments B
Crossover Wiring
If the twisted-pair cable is to join two ports and either both ports are labeled with an “X” (indicating MDI-X) or neither port is labeled with an “X” (which indicates MDI), a crossover must be implemented in the wiring. (When auto-negotiation is enabled for any RJ-45 port on the switch, you can use either straight-through or crossover cable to connect to any device type.)
You must connect all four wire pairs as shown in the following diagram to support Gigabit Ethernet connections.
EIA/TIA 568B RJ-45 Wiring Standard 10/100BASE-TX Crossover Cable
| | White/Orange Stripe | |
| | Orange | |
| 1 | White/Green Stripe | 1 |
End A | 2 | | 2 |
| 3 | Blue | 3 |
| 4 | | 4 |
| 5 | White/Blue Stripe | 5 |
| 6 | Green | 6 |
| 7 | 7 |
| 8 | White/Brown Stripe | 8 |
| | |
Brown
Figure B-3 Crossover Wiring
1000BASE-T Pin Assignments
All 1000BASE-T ports support automatic MDI/MDI-X operation, so you can use straight-through cables for all network connections to PCs or servers, or to other switches or hubs.
The table below shows the 1000BASE-T MDI and MDI-X port pinouts. These ports require that all four pairs of wires be connected. Note that for 1000BASE-T operation, all four pairs of wires are used for both transmit and receive.
Use 100-ohm Category 5, 5e or 6 unshielded twisted-pair (UTP) or shielded twisted-pair (STP) cable for 1000BASE-T connections. Also be sure that the length of any twisted-pair connection does not exceed 100 meters (328 feet).
Table B-2 1000BASE-T MDI and MDI-X Port Pinouts
Pin | MDI Signal Name | MDI-X Signal Name |
| | |
1 | Bi-directional Data One Plus (BI_D1+) | Bi-directional Data Two Plus (BI_D2+) |
| | |
2 | Bi-directional Data One Minus (BI_D1-) | Bi-directional Data Two Minus (BI_D2-) |
| | |
3 | Bi-directional Data Two Plus (BI_D2+) | Bi-directional Data One Plus (BI_D1+) |
| | |
