Straight cables are used to connect PCs or other equipment to a HUB or Switch. If your connection is PC to PC or HUB to HUB you MUST use a Crossed cable.

Crossed cables are used to connect PCs to one other PC or to connect a HUB to a HUB. Crossed cable are sometimes called Crossover, Patch or Jumper cables.

RJ45 Connector Pin Numbering

RJ-45 connector

RJ-45 connector




RJ-45 conductor data cable contains 4 pairs of wires each consists of a solid colored wire and a strip of the same color. There are two wiring standards for RJ-45 wiring: T-568A and T-568B. Although there are 4 pairs of wires, 10BaseT/100BaseT Ethernet uses only 2 pairs: Orange and Green. The other two colors (blue and brown) may be used for a second Ethernet line or for phone connections. The two wiring standards are used to create a cross-over cable (T-568A on one end, and T-568B on the other end), or a straight-through cable (T-568B or T-568A on both ends).






To create a straight cable, you’ll have to use either T-568A or T-568B on both ends of the cable.

To create a cross-over cable, you’ll wire T-568A on one end and T-568B on the other end of the cable.

Pin Number Designations

There are pin number designations for each color in T-568B and T-568A.

Pin T-568-B T-568-A
Colour Pin Name Colour Pin Name
1. Orange Stripe Tx+ Green Stripe Rx+
2. Orange Tx- Green Rx-
3. Green Stripe Rx+ Orange Stripe Tx+
4. Blue Not Used Blue Not Used
5. Blue Stripe Not Used Blue Stripe Not Used
6. Green Rx- Orange Tx-
7. Brown Stripe Not Used Brown Stripe Not Used
8. Brown Not Used Brown Not Used