Classification of LAN cables

Twisted pair (Twisted pair) is divided into shielded (Shielded Twisted pair, STP) and unshielded (Unshielded Twisted pair, UTP). The so-called shielding means that the signal wires inside the LAN cable are wrapped with a layer of metal mesh, and the shielding layer is the insulating sheath. The shielding layer can effectively isolate the interference of external electromagnetic signals.

UTP is currently the most frequently used network cable in local area networks. This kind of LAN cable is wrapped with 8 signal wires in a plastic insulating sheath. Two of them are entangled with each other in a pair, forming a total of four pairs. The twisted pair is also named. The purpose of twisted pairs twisted with each other is to use the electromagnetic field generated by the current in the copper wire to cancel the interference of adjacent lines and reduce the interference from the outside world. The number of times each pair of wires are entangled per inch of length determines the anti-interference ability and the quality of communication. The tighter the winding, the higher the communication quality and the higher the network data transmission rate. Of course, its cost is also higher.