The following diagram and tables show the standard RJ-45 pin assignment and the media direct interface signal
For the 8 cables at RJ-45, only 4 cables are using for Transmit (Tx) and Receive (Rx), pin 4,5,7 and 8 is not using.
Let us recall the UTP color code utp color code or so called RJ-45 cable, here is the pin out and color code diagram for straight cable.
As mention previously, T568A’s standard using at older generation, while start from 2002 onward, we follow T568B’s standard. TIPS: Do you know that cable with 1 end T568A and another end with T568B, will be a standard cross cable? Check out ur self for the color code.
Below is the pin out and color code diagram for cross cable.