1. Classification of Network Cables

By Performance: The most common network cables can be divided into CAT.5,CAT.5e,CAT.6, CAT.6a,CAT.7, andCAT.8.

By Material: They can be made of oxygen-free copper, aluminum wire, copper-clad aluminum, and aluminum-iron types. The higher the copper content, the better the performance of the cable, and the higher the price.

By Usage Environment: Divided into unshielded and shielded network cables.

The differences are:

Appearance: Compared to unshielded cables, shielded cables have a shielding layer of aluminum foil or metal mesh, which can be single-shielded or double-shielded depending on the number of shielding layers.

Function: Due to the presence of a shielding layer, shielded cables are highly resistant to external interference. In environments with strong

interference, shielded cables are more stable and secure.
Shielded twisted pair cables are wrapped in aluminum platinum to reduce signal interference, but they cannot completely eliminate it. Shielded twisted pair cables are relatively expensive and more difficult to install than unshielded network cables. Unshielded network cables do not have a shielding jacket, are smaller in diameter, save space, are lightweight, easy to bend, easy to install, minimize or eliminate near-end crosstalk, are flame retardant, and are independent and flexible, suitable for structured cabling.
In practical work, shielded network cables require all materials to be shielded, including shielded cables, shielded connectors, and shielded equipment. Proper grounding is needed when using them, as grounding can better shield external signals. Shielded network cables have high requirements for the implementation of structured cabling; all components in the system must have shielding functions and be well-grounded to be effective; otherwise, the shielding effect will be poor.

2. Performance Identification of Network Cables

Cable Marking Recognition Method: The specifications of the network cable are marked on the cable sheath every meter. 
Flame Resistance Test: Genuine network cables have flame resistance. When the outer sheath is burned, it will gradually melt and deform, but the sheath will not catch fire. Otherwise, the network cable is definitely substandard.
Magnet Test: A magnet can identify iron core wires. If the network cable is attracted by a magnet, it indicates that the cable is an iron core wire. Iron core wires have higher resistance, severely affecting the transmission rate and distance, and are not recommended for use.
Direction of Cable Twisting: The direction of cable twisting should be counterclockwise, not clockwise, as clockwise twisting can affect the transmission quantity and distance.
Length: The standard length of genuine network cables is 305 meters. Fake cables may be shorter.

3. Network Cable Sequence

Network cable connectors are either straight-through or crossover. Straight-through cables have both ends following either the T568A or T568B standard; crossover cables use the T568A standard on one end and the T568B standard on the other. Nowadays, network devices support auto-MDI/MDIX, so both straight-through and crossover cables can be used. The T568A sequence is: white-green, green, white-orange, blue, white-blue, orange, white-brown, brown. The T568B sequence is: white-orange, orange, white-green, blue, blue-white, green, white-brown, brown.

T568A Wiring Sequence: ①White-Green ②Green ③White-Orange ④Blue ⑤White-Blue ⑥Orange ⑦White-Brown ⑧Brown

T568B Wiring Sequence: ①White-Orange ②Orange ③White-Green ④Blue ⑤Blue-White ⑥Green ⑦White-Brown ⑧Brown

4. Testing of Network Cables

After making the connectors, the network cables need to be tested. Typically, a cable tester or a project treasure is used to test whether the connectors are connected. In some high-standard projects, Fluke brand equipment can be used for testing. The cable tester has nine lights. If it is an unshielded network cable inserted into the tester interface, the cable connection from 1-8 will light up sequentially. If it is a shielded cable test, in addition to 1-8 lighting up sequentially, the corresponding shielded cable G light will also light up.

5. Extension of Network Cables

In actual work, sometimes the estimated cable length is insufficient, and the reserved cable is too short, which can be extended using connectors, terminal blocks, soldering, or twisting methods. Among them, the connector is the simplest and most commonly used method.

Connector Method: Make a connector on one end of the insufficiently long network cable and plug it directly into the connector. On the other end, use another connector to connect another network cable. Using connectors is a simple and cost-effective solution to extend network cables.
Terminal Block Method: Strip both ends of the cable to be extended, exposing 3-5 cm, and ensure the colors match when connecting.
Soldering Method: Solder the eight cores of the network cable, ensuring the colors match. Compared to the connector method, soldering requires higher skills and professional tools. This method is not recommended.
Twisting Method: Network cables can be manually connected like electrical wires. Strip the eight cores of the network cable, twist two cables of the same sequence together, and wrap them with insulating tape. This method is only suitable for emergency or temporary testing and not for long-term use.

6. Selection of Network Cables

For small enterprises (10-30 people): It is recommended to use a Fast Ethernet network and Enhanced Cat5 cables to meet daily office requirements.
For medium-sized enterprises (50-100 people): It is recommended to use a Gigabit network and choose Cat6 twisted pair cables to ensure sufficient bandwidth for the office's internal and external networks to meet the staff's network needs.
For large enterprises (over 100 people): It is generally recommended to choose a Gigabit network and Cat6 or Enhanced Cat 6 twisted pair cables. Network equipment should use Cat7 patch cables to ensure bandwidth.
For general households: Enhanced Cat5 cables can meet daily requirements, but with the rapid development of Gigabit networks, it is best to use Cat6 cables directly. It is recommended to pre-embed Cat6 cables during home renovations. Since there is no large-scale interference in home scenarios, unshielded network cables are sufficient.