Standard Cat-5 Wiring Schemes
This section covers the basics of wiring Cat-5 cable for wired networks. This information is not necessary for basic home networking, and is directed towards a more advanced technical audience.
There are two standards for wiring CAT 5 cable: 568-A and 568-B. Below, you will find the specification and color codes for both. If you wish to create a cable that will be used to connect a workstation with a network device such as a hub or switch, you will want to follow these basic schemes. Be sure to be consistent. If you are wiring one end with the 568-A standard, make sure you wire the other end in the same manner.
568-A
| Pin | Color | Pair | Description |
|---|---|---|---|
| 1 | white/green | 3 | RecvData + |
| 2 | green | 3 | RecvData - |
| 3 | white/orange | 2 | TxData + |
| 4 | blue | 1 | Unused |
| 5 | white/blue | 1 | Unused |
| 6 | orange | 2 | TxData - |
| 7 | white/brown | 4 | Unused |
| 8 | brown | 4 | Unused |
568-B
| Pin | Color | Pair | Description |
|---|---|---|---|
| 1 | white/orange | 2 | TxData + |
| 2 | orange | 2 | TxData - |
| 3 | white/green | 3 | RecvData + |
| 4 | blue | 1 | Unused |
| 5 | white/blue | 1 | Unused |
| 6 | green | 3 | RecvData - |
| 7 | white/brown | 4 | Unused |
| 8 | brown | 4 | Unused |
Cross-Over
In general, the patch cords that you use with your Ethernet connections are "straight-through," which means that pin 1 of the plug on one end is connected to pin 1 of the plug on the other end (for either standard). The only time you cross connections in 10BaseT is when you connect two Ethernet devices directly together without a hub, or when you connect two hubs together. In these instances, you will need a "cross-over" patch cable, which crosses the transmit and receive pairs. An easy way remember how to make a cross-over cable is to wire one end with the T-568A standard and the other with the T-568B standard.
