How to determine the quality of a network cable

Network cables are an important component of network connections, and their quality directly affects the stability and speed of the network. Poor-quality network cables may cause signal attenuation, unstable connection or even network disconnection. Therefore, it is very important to judge the quality of the network cable. This article will provide a detailed introduction on how to determine the quality of network cables from several aspects, including appearance inspection, specification identification, testing tools, and actual usage.

I. Check the appearance of the network cable

1. Wire quality

Outer sheath: Observe whether the outer sheath of the network cable is smooth, soft and elastic. The outer sheath of high-quality network cables is usually made of environmentally friendly PVC or low smoke zero halogen materials, with a smooth surface and no obvious bumps or bubbles. The outer sheath of inferior network cables may be relatively hard, prone to cracking or have a pungent smell.

Network cable core: Distinguish by the purity and color of the network cable core

Cut open the outer layer of the sheath, remove the insulation, and cut a small section of the conductor to observe whether the copper color of the cross-section is uniform. If it is pure copper, it will present a uniform golden color. However, if iron or aluminium, or other alloys are mixed in, obvious white spots or black spots can be seen.

In addition, when the surface of a conductor copper is exposed to a positive flame, the outer color turns black, while the inner color remains unchanged yellow. After the blackened part is wiped off, the copper still retains its original color. But if it contains iron, no matter how you wipe it, it will always be a dull black.

To determine if the network cable is seriously mixed with iron, you can cut a small section of the copper core, remove the plastic covering it, and see if it can be lifted with a screwdriver. This is because the screwdriver tip is magnetic. If it is pure copper, it cannot be adsorbed. However, it is different when iron is mixed in. Counterfeit products mixed with iron can reduce costs, but it will cause a mismatch in cable resistance, shorten the transmission distance, and reduce the transmission speed, etc.

Wire diameter: Standard Cat5e and above network cables use 23AWG or 24AWG (approximately 0.5mm) pure copper wire cores. Poor-quality wires may use copper-clad aluminum (CCA) as thin as hair or even iron cores. When held in hand, they feel noticeably light and the wire body is soft, limp and weak.

2. Quality of the crystal head

The RJ45 connector is a key component of network cables. Check whether the plastic of the crystal head is strong and transparent, and whether the metal contacts are gold-plated or nickel-plated (gold-plated contacts have better electrical conductivity). The contacts of low-quality crystal heads may have oxidation marks or be loose.

Gold finger luster: The high-quality crystal head contacts have a thick and uniform gold plating layer, presenting a rich golden color. Inferior products are dull, thin and even reveal the underlying white metal (such as nickel), which is highly prone to oxidation and blackening, leading to poor contact.

L-line sequence "bone structure" : Confirm whether the 8 fine wire cores inside the crystal head are neatly arranged and precisely positioned in accordance with the T568A or T568B standards (especially check the four key transmission cores 1, 2, 3, and 6). Disordered wiring is a common culprit for network disconnection.

Snap toughness: Is the snap still firm after repeated insertion and removal? A loose crystal head will frequently disconnect.

3. Cable identification

High-quality network cables usually have clear specification information printed on their outer sheaths, such as "CAT5e", "CAT6", "CAT7", etc., as well as brand, production batch and other information. If the label is unclear or completely absent, it may be a substandard product.

CAT5E/CAT6 / CAT6A, etc. (Category identifiers)

'UTP' (unshielded) or 'STP'/' FTP '(shielded type)

Certification marks (such as' UL ETL ')

Length marking (such as' 305m ')

Wire gauge (such as' 24AWG ')

Ii. Identify the specifications of the network cable

The specifications of network cables directly determine their performance. The following are the common types of network cables and their characteristics:

·CAT5e: Supports Gigabit Ethernet with a maximum bandwidth of 100MHz, suitable for home use or small offices.

·CAT6: Supports 10-Gigabit Ethernet (short distance), with a bandwidth of 250MHz, and has stronger anti-interference ability.

·CAT6a: Supports a longer 10-gigabit transmission distance with a bandwidth of 500MHz.

·CAT7: With a bandwidth of up to 600MHz, it is suitable for high-performance data centers or professional applications.

Check the category label on the outer sheath of the network cable to ensure it meets your network requirements. If the marking is not clear or the specification is too low, it may not be suitable for high-speed networks.

In addition, network cables are divided into shielded network cables (STP) and unshielded network cables (UTP) :

· Shielded network cable: It has a metal shielding layer inside, strong anti-electromagnetic interference ability, and is suitable for complex electromagnetic environments.

· Unshielded network cables: Lower prices, suitable for ordinary home or office environments.

Iii. Use professional tools for testing

1. Network cable tester

The network cable tester is a commonly used tool for judging the quality of network cables. It can detect the on-off status of network cables, whether the wire sequence is correct, and whether there is a short circuit or crosstalk. The usage method is as follows:

• Insert both ends of the network cable into the corresponding interfaces of the tester.

• Start the tester and observe whether the sequence of the indicator lights is consistent with the standard line sequence (T568-B or T568-A).

• If there is an open circuit, short circuit or incorrect wire sequence, the tester will clearly display the problem.

2. Network analyzer

For more professional tests, network analyzers (such as Fluke network cable analyzers) can be used to measure key electrical performance parameters of network cables, including signal attenuation, crosstalk, return loss, and delay deviation. These data can help determine whether the network cable truly complies with standards such as Cat5e/6/6A.

3. Multimeter

If there is no dedicated tester, a multimeter can be used to measure the continuity of the network cable. Test each of the 8 cores in the network cable one by one to ensure that each core can conduct normally.

Iv. Performance in Actual Use

1.Network speed and stability

Connect the network cable to the router and the device to test whether the network speed meets expectations. For instance, connect a gigabit router and a computer with a gigabit network cable and run a speed test (such as Speedtest). If the speed is much lower than expected, it might be a problem with the quality of the network cable.

2. Packet loss rate and latency

Use command-line tools such as ping or tracert to test the packet loss rate and latency of the network. High-quality network cables should have a packet loss rate close to 0% and low latency under normal conditions. If packet loss or high latency occurs frequently, it may be due to poor quality of the network cable.

3. Long-distance transmission test

The transmission distance of network cables is also an important indicator for judging their quality. CAT5e network cables theoretically support transmission over 100 meters, while CAT6 and CAT7 support even longer distances. If the network cable shows signal attenuation within a relatively short distance, it indicates poor quality.

V. Other Matters needing Attention

1. Avoid excessive bending

The copper core or shielding layer inside the network cable may be damaged after excessive bending, resulting in a decline in performance. Check if the network cable is overly squeezed or tangled.

2. Brand and Price

Choosing network cables from well-known brands (such as TP-Link, Belkin, Amp, ZORA, etc.) ensures better quality. Network cables with excessively low prices often cut corners in terms of materials and craftsmanship.

3. Environmental adaptability

If the network cable is used outdoors or in a high-temperature and high-humidity environment, a dedicated network cable with waterproof, sun-proof or high-temperature resistant properties should be selected.

Vi. Summary

To determine the quality of a network cable, it is necessary to comprehensively consider its appearance, specifications, test results and actual performance in use. The quality of network cables can be effectively evaluated by checking the quality of cables and crystal heads, confirming the category of network cables, using testing tools and observing network performance. When purchasing network cables, it is recommended to choose a regular brand and select the appropriate specification based on actual needs to ensure the stability and speed of the network connection.

I hope this article can help you easily judge the quality of network cables and create an efficient and stable network environment!