Straight through cable Wiring Diagram Color Code

Here a ethernet  RJ45  Straight cable Wiring Diagram witch color code category 5,6,7 a Straight Through Cables are one of the most common type of patch cables used in network world these days. These cables are used to connect different devices over a network, for instance you have to use Straight Cable if you are connecting

  • PC to HUB/Switch
  •  Switch to Router



These Straight Through Cables can be made using UTP (unshielded twisted pair) cables. These UTP cables ends are usually terminated at RJ45 (registered jack 45) connector.
UTP cables comes with eight wires small wires, which are twisted in four pairs. Each pair has different color scheme. Only two pairs are used in 10/100 Mbps networks, while in gigabit all four pairs are used.
To understand Straight Through Cable working it’s important to understand the color coding scheme of wires that is used.

Straight  Wiring Diagram Standards : EIA/TIA T568A & T568B :

EIA/TIA 568A & 568B are two straight cable color coding standards. Following is detail of these standards

T568A Wiring diagram :

This color coding standard was introduced in mid of 1980’s, it’s not widely used these days. Below is straight through wiring diagram of 568A color coding.

 Following table illustrates which pin is sending and which is receiving data.

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                                    –

T568B wiring diagram

568B is most widely used color coding standard these days and is used by cable manufacturers world wide. All of Straight through cable these days are following 568B color coding. Below is straight through wiring diagram of 568A

The color coding used in 568B is as follows 

Pin No             Wire Color         Transmitting/Receiving  

1                  White/Orange         Transmitting
2                  Orange                    Transmitting
3                  White/Green           Receiving
4                   Blue                             –
5                  White/Blue                   –
6                  Green                      Receiving
7                  White/Brown                –
8                  Brown                           –

An important point to consider is that pin 1 & 2 are transmitting while 3 & 6 are receiving at both ends. You may say Pin 1 and 2 at both ends is sending, but that’s not the case. Consider we have connected a PC with a Hub, Pin 1 at PC will be Sending data while Pin 1 at switch will transform itself into receiving Bit. Same is followed by remaining three pins.

Difference between 568A and 568B

There is slight difference between 568A and 568B , only orange and green pairs are swapped rest of two pairs are same in both combination.

Structured Cabling is an important part of your network to work smoothly. An important concept to remember is, whether you make 568A or 568B make sure both ends of have same combination, which means if you are making 568A make sure both ends of your cable terminating at RJ45 are using 568A color coding and same is true when you make 568B. In other words 568A will only work with 568A not with 568B and vice versa.

With Auto-MDIX (automatic medium-dependent interface crossover) devices can automatically detect which cable connection (straight or crossover cable ) is required and switch over to it automatically.