How to distinguish network cables

How to distinguish network cables
Distinguishing network cables can usually be done from three main dimensions: performance level, shielding type, and wiring sequence. Here is a detailed method for distinction:

1. By performance level classification (look at the appearance label)
This is the most core method of distinction. Usually, you can find the "Cat" symbol on the outer skin of the network cable. The larger the number, the newer the version, the more advanced the technology, and the wider the bandwidth. Also, the price is higher. Currently, the mainstream types of network cables include:
Cat5 (five-category cable): Bandwidth 100 MHz, maximum transmission rate 100 Mbps. It has been largely phased out and is not recommended for new network installations.
Cat5e (enhanced five-category cable): Bandwidth 100 MHz, supports gigabit (1 Gbps) transmission. It is the mainstream choice for home and small business gigabit networks, with high性价比.
Cat6 (six-category cable)： Bandwidth 250 MHz， supports gigabit transmission. In some short-distance scenarios， it can reach 10 Gbps. Its internal usually has a "crossbar" isolation structure， and the wire cores are thicker.
Cat6A (super six-category cable)： Bandwidth 500 MHz， can stably support 10 Gbps transmission over a 100-meter distance. It is the standard for data centers and high-speed networks.
Cat7/Cat8 (seven-category/eight-category cable)： Extremely high bandwidth， supports transmission speeds ranging from 1 Gbps to 40 Gbps. However， the cost is high， and Cat8 has a very short transmission distance (less than 30 meters)， mostly used in special industries or cabinet-based equipment interconnection.
2. By shielding type classification (look at the internal structure)
According to whether the network cable has a metal shielding layer inside， it can be divided into two types：
Unshielded Twisted Pair (UTP)： No shielding layer inside. The advantages are low cost， light weight， good flexibility， and easy bending， suitable for environments with weak electromagnetic interference in homes and offices， and the most widely used.
Shielded Twisted Pair (STP)： Has a metal shielding layer (such as aluminum foil or woven mesh) inside. The advantages are strong anti-interference ability， reducing radiation and preventing information from being eavesdropped， suitable for strong electromagnetic interference areas such as data centers and industrial environments. However， it is more expensive and has more stringent installation requirements.
3. By wiring sequence classification (look at the RJ45 connectors at both ends)
According to whether the wiring sequence of the RJ45 connectors at both ends is the same， it can be divided into two types：
Straight-through cable： The wiring sequence of both ends is exactly the same (usually follows the T568B standard). It is mainly used for connections between different network devices， such as computer to switch， switch to router， etc.
Crossover cable： One end follows the T568A standard， and the other end follows the T568B standard. It is mainly used for direct connections between the same network devices， such as two computers directly connected， switch to switch， etc.
Note： Currently， most network devices have self-negotiation function in ports. Once enabled， whether using straight-through or crossover cable， normal communication can be achieved.

Summary and suggestions： When purchasing and distinguishing network cables in daily life， the most direct method is to check the "Cat" label on the outer skin of the network cable to determine the performance level， and based on the actual usage environment (whether there is strong interference) to decide whether to purchase a cable with a shielding layer.