Line sequence of direct and Cross Network cables

There are two international standards for the production of twisted pair wires: EIA/tia568a and EIA/tia568b. There are two main connection methods for twisted pair wires: straight-through cables and cross cables. Simply put, the straight-through cable means that both ends of the crystal head adopt the t568a standard or the t568b method at the same time, while the crossover cable is made of the t586a standard at one end of the crystal head, the other end adopts the t568b standard, that is, 1 and 2 of a crystal head correspond to 3 and 6 of B crystal head, and 3 and 6 of a crystal head correspond to 1 and 2 of B crystal head.

The line sequence described in t568a is from left to right:

The line sequence described in t568b standard is from left to right: