Baimu Line is generally called Grade 5 Line or Super Grade 5 Line. The thread is thin, and there is no plastic core in the thread. 1000 meter line is a 6-grade line. Eight small lines in the line are thicker than the 5-grade line, and a plastic core is added in the line, which increases the quality of the line. The eighth cable is made of pure copper core, so when you buy the network cable, touch it with your hands first to see if it is hard or not. The harder the better. The hard wire is twisted tightly. Cut the clamp with pliers to see if the small thread inside is copper. If it's white, it's a fake wire. If aluminum alloy is added, don't buy it, because copper has better transmission in metal than aluminum-iron wire, which is why copper wire is more expensive than aluminum wire.
There is only the difference between shielded wire and unshielded wire, including crystal head (cable head).
Because the network cable transmission adopts electric transmission to convert signals, there is a definition: the network scheme of full twisted pair transmission is called electric port scheme; The network cable interface provided above the switch is also called the power port, so we often hear that the XX switch has 24 power ports, and the two optical ports probably mean this. The specification of electric port transmission network cable interface is RJ-45.
Go back to the topic and explain the difference between shielding and non-shielding;
Above, we have explained that twisted pair transmission is electric transmission, which is generally interfered by external media, leading to the decline of network transmission mode, so it is divided into shielded and unshielded; The shielding wire is usually a layer of tin foil paper, which looks a bit like smoke after opening the outermost plastic skin. This tin foil paper is a shielding layer to prevent external media from interfering with the transmission of network cables. For unshielded network cables, there is no such material.
This material can effectively shield electromagnetic interference in the air and prevent it from affecting the transmission of network cable models. The shielding material is four groups of eight wires with different colors that we want to use. Shielded network cables are relatively expensive in the market, and the price is about 1000 yuan per box, while the market price of unshielded 6-kilometer lines ranges from 400 to 700.
Internet cafes use fewer shielded wires. As long as you are willing to invest money, the use effect is naturally better than that without shielding, and so is the crystal head. The price of shielding crystal head is generally high; Gundam 10, one hundred yuan. In institutions, banks and enterprises, there are many shielded wires and connectors. Laying network cable in the field is a very important project, so in order to prevent interference in the air when using unshielded network cable, PVC pipes can be used to install network cable, and it is not recommended to go underground when wiring, and it is generally best to go to the wall or ceiling; The distance between the wall and the ground should be more than 30 cm, and the distance between the network cable and the wire should be more than 20 cm. If possible, pass through the pipeline, or just pass the network cable through the pipeline; Because the current increases and the load increases after ordinary wires and patch panels are electrified, electromagnetic fields will be generated, which will interfere with the transmission of network cables. Once, when I was plugging in the internet system, the new machine in an internet cafe could not be plugged in quickly. Finally, the reason was found out, and it was found that the network cable of a machine was 2 meters long, and there was a patch panel together with a 2.5 square wire, but the wire did not pass through the pipeline network cable, which led to the network jam of this machine and affected the speed of the whole network plug-in. As a result, the network plug-
I'll teach you one trick I'm used to most: If someone asks you how many boxes of network cables you want to buy, how many boxes do you even know?
I remember in 2003, I went to an Internet cafe to apply for a job. A person who doesn't know whether it's a technician or a boss asked me, do you know how many meters a box of network cables is? I haven't known for a long time, hehe.
A box of standard network cable is 300-305 meters. When planning how many boxes to buy in Internet cafes, we can learn from each other's strengths. According to the plan that the network cable between a machine and a switch is 10 meter, then 1 box is planned to be 300 meters. Considering that there are mainline servers available, 100 Internet cafes usually buy 4 boxes.