Crossover Cable Color Code Wiring Diagram

look for a Crossover cable color code with a wiring diagram for rj45 Crossover Cable or Cross Cable is a type of Ethernet Cable that is used to connect similar types of networking devices, in contrast to Straight Through Cable which is used to connect different devices. For instance, you need cross cable if you are connecting

• PC to PC
• Switch to Switch
• Router to Router

To understand Crossover Cable working, it's important to understand the crossover cable color code i.e. pattern in which wires are connected to RJ-45 connector. We start by looking at the diagram.

Crossover Cable Wiring Diagram

We can see in the above diagram that the left side is following 568B color coding and the Right end is following 568A color coding.

Crossover Cable Color Code TIA 568B

The following Table illustrates TIA 568B color coding scheme which is applied on the left end of the cable in Crossover Cable Wiring Diagram.

Pin No Wire Color       Transmitting/Receiving
1        Orange/White       Transmitting
2          Orange               Transmitting
3       Green/White       Receiving
4          Blue                    -
5      White/Blue                    -
6       Green               Receiving
7      White/Brown            -
8       Brown                    -

Crossover Cable Color Code TIA 568A

This color-coding standard is applied on the right end of the cable in Crossover Cable Wiring Diagram.

Pin No   Wire Color Transmitting/Receiving
1        White/Green Transmitting
2         Green         Transmitting
3      White/Orange Receiving
4            Blue              -
5     White/Blue              -
6       Orange         Receiving
7     White/Brown      -
8       Brown              -

To make a crossover cable one end of the UTP cable has to follow either TIA 568 A or B Color coding, while the other end must have different color coding. In short, both ends must have different color coding schemes. Use the following guidelines while making the cross cable.

• If one end of the cable has 568A color coding then the other end must follow 568B color coding. 
• If one end of the cable has 568B color coding then the other end must follow 568A color coding.

This is different than straight through cable in which both ends of the cable must have the same color-coding standard at both ends, look for a Straight cable color code.

Why to Use different oF crossover cable color coding

As in UTP, there are eight wires twisted together in four pairs. In Fast Ethernet pin 1 and 2 of the RJ-45 connector are reserved for transmission while pin 3 and 6 of the RJ-45 connector are reserved for receiving. As pin 1 is transmitting so it cannot be connected to pin 1 at the other end since that too is transmission mode. It follows that pin 1 should be connected to pin 3, which is in receiving mode.
To sum up pin 1 and 2 from device A is connected to pin 3and 6 of device B, while pin 3 and 6 of device A are connected to pin 1 and 2 of device B.
It's named crossover cable since wires are cross-connected at both ends of RJ-45 connectors

Automatic Medium-Dependent Interface Crossover (Auto-MDIX)

It's important to have a good understanding of color-coding schemes in crossover and straight-through cable but today almost all networking devices support Auto-MDIX, by which devices can automatically detect which cable is required and switch to it automatically. So if you are connecting similar devices and you only have a straight-through cable, you can use it.