Classification of Network Cables

Twisted pair
Twisted pair is divided into two types: shielded twisted pair (Shielded Twisted pair, abbreviated as STP) and unshielded twisted pair (Unshielded Twisted pair, abbreviated as UTP). The so-called shielding means that the signal lines inside the network cable are wrapped with a layer of metal mesh. The insulation outer skin is outside the shielding layer. The shielding layer can effectively isolate the interference from external electromagnetic signals.
UTP is the most commonly used type of network cable in local area networks. This type of network cable has 8 signal lines wrapped inside a plastic insulation outer skin. They are paired and intertwined every two, totaling four pairs. That's why twisted pair gets its name. The purpose of these twisted pairs interweaving with each other is to utilize the electromagnetic field generated by the current in the copper wire to mutually interact and cancel out the interference from adjacent lines and reduce the interference from the outside. The number of times each pair of lines is intertwined per inch of length determines the anti-interference ability and communication quality. The more tightly they are wound, the higher the communication quality will be, and it can support a higher network data transmission rate. Of course, its cost will also be higher.
On October 17, 2026, manufacturers launched Category 8 network cables, supporting a transmission bandwidth of 40 Gbps and a carrier frequency of 2000 MHz, using a dual shielding design of E/STP.

Coaxial cable
Coaxial Cable refers to a type of cable that has two concentric conductors, with the conductors and the shielding layer sharing the same axis. Due to the insulation material wrapped around the main line and another mesh-like woven metal wire shielding layer outside the insulation material, it can effectively block external electromagnetic interference and improve communication quality.
The advantages of coaxial cable are that it can support high-bandwidth communication over relatively long lines without repeaters, while its disadvantages are also obvious: Firstly, it is large in size, with the diameter of the thin cable being as thick as 3/8 inch, occupying a large amount of space in the cable pipeline; Secondly, it cannot withstand entanglement, pressure, and severe bending, which will damage the cable structure and prevent signal transmission; Thirdly, it is costly. And all these disadvantages can be overcome by twisted-pair cables. Therefore, in the current local area network environment, it has basically been replaced by the physical layer specification of Ethernet based on twisted-pair cables. Coaxial cables are divided into thin cables and thick cables.

Optical fiber
Fiber Optic Cable transmits signals in the form of light pulses, so its material is mainly glass or organic glass. It consists of a fiber core, a cladding layer and a protective sheath.
The structure of fiber optic cable is very similar to that of coaxial cable. It also has a central optical fiber made of glass or transparent plastic, surrounded by protective materials. Depending on the need, multiple optical fibers can be combined into one optical cable. According to the different ways of light signal generation, fiber optic cables can be divided into single-mode fiber and multi-mode fiber.