Network Cabling basics: What are the differences between crossover lines and direct connections?

There are 8 wires in the cable, divided into 4 pairs, each of which is a pair of twisted pair wires, in turn: (orange, orange); (green, green); (Blue, Blue ); (brown, white)

The sorting order of 568a is from left to right: green white, green, orange white, blue, blue white, orange, brown white, and brown.

568b: Orange, orange, green, blue, blue, green, brown.

Among them, 1 and 2 are used to send data, 3 and 6 are used to receive data, 4 and 5 are used to transmit voice, and 7 and 8 are used to transmit power.

The so-called crossover refers to the 568a standard and 568b standard twisted pair wires at the other end.

Direct Connection means that both ends are 568a or 568b standard twisted pair wires.

By the way, many friends only ensure the order of the two ends of the line to correspond one by one when doing the RJ45 head, but do not follow the 568a/568b line standards. Although the network can be connected in this way, the anti-interference performance of such lines is very poor, such as slow transmission speed and good or bad network conditions. We hope that you will follow the standards when working on the network cable, and the network cable length should be no less than 1.5 meters based on actual engineering experience, which is necessary to improve the network stability!

Direct connections are required when the following devices are connected:

1. Connect A vswitch or hub to a vro;

2. The computer (including servers and workstation) is connected to a vswitch or hub;

3. The vswitch and the vswitch are connected through the uplinks port.

When these devices are connected, you need to use the crossover line:

1. Computer and router connection;

2. Connect the vswitch to the vswitch;

3. Connection Between hub and hub;

4. Two PCs are directly connected;

5. connection between a vro interface and other vro interfaces;

6. Connect the ADSL modem of the Ethernet interface to the NIC interface of the PC.

In short, the same layer of devices are connected with a cross line, and different layers of devices are connected with a direct line.