1. Introduction to various types of network cable knowledge:
Class 1 cable: mainly used to transmit voice (a class of standards was mainly used for telephone cables before the early eighties), different from data transmission.
Category 2 Line: 1MHZ transmission frequency for voice transmission and data transmission with a maximum transmission rate of 4Mbps, commonly found in older token networks that use the 4MBPS specification token delivery protocol.
Category 3 cable: The cable specified in the ANSI and EIA/TIA568 standards, the transmission frequency of the cable is 16MHz, used for voice transmission and the transmission rate of up to 10Mbps is mainly used for 10BASE–T.
CAT 4 cable: This type of cable has a transmission frequency of 20MHz, which is used for voice transmission and data transmission with a maximum transmission rate of 16Mbps, and is mainly used for token-based LANs and 10BASE-T/100BASE-T.
CAT 5 cable: This type of cable increases the winding density, jacketed with a high-quality insulation material, transmission rate of 100MHz, used for voice transmission and data transmission with a maximum transmission rate of 100Mbps, mainly used for 100BASE-T and 10BASE-T networks. This is the most commonly used Ethernet cable.
Super Cat 5 line: Cat 5 has small attenuation, less crosstalk, and higher attenuation-to-crosstalk ratio (ACR) and signal-to-noise ratio (StructuralReturn Loss), smaller time delay difference, and greatly improved performance. Category 5 cables are mainly used for Gigabit Ethernet (1000Mbps).
Category 6 line: The transmission frequency of this type of cable is 1MHz~250MHz, and the comprehensive attenuation crosstalk ratio (PS-ACR) of the Category 6 wiring system should have a large margin at 200MHz, which provides twice the bandwidth of Category 5. The transmission performance of Category 6 cabling is much higher than that of Category 5 standards, and it is most suitable for applications with transmission rates higher than 1Gbps. An important difference between Cat 6 and Cat 5 is improved performance in terms of crosstalk and return loss, which is critical for the next generation of full-duplex high-speed network applications. The basic link model is canceled in the six types of standards, and the wiring standard adopts a star topology, and the required wiring distance is: the length of the permanent link cannot exceed 90m, and the channel length cannot exceed 100m.
CAT 7: It is mainly to adapt to the application and development of 10 Gigabit Ethernet technology. BUT IT IS NO LONGER AN UNSHIELDED TWISTED PAIR, BUT A SHIELDED TWISTED PAIR, SO IT CAN PROVIDE A COMPREHENSIVE ATTENUATION-TO-CROSSTALK RATIO OF AT LEAST 500MHZ AND AN OVERALL BANDWIDTH OF 600MHZ, MORE THAN TWICE THAT OF CAT SIX AND SUPER SIX CABLES, AND A TRANSMISSION RATE OF UP TO 10Gbps. In the seven types of cables, each pair of wires has a shield, and together the four pairs have a common large shield. From a physical point of view, the additional shielding layer allows the CAT 7 wire to have a larger wire diameter.
Category 8 cable: is the latest generation of network cable, and Category 7 network cable is the same as double-layer shielding (SFTP), it has two wire pairs, 2000MHz ultra-high wide screen, transmission rate up to 40Gb/s, but its maximum transmission distance is only 30m, so it is generally used for the connection of servers, switches, distribution frames and other equipment in short-distance data centers.
Second, the judgment of the quality of the network cable:
1. Wire core
First of all, the network cable transmission quality using copper core is the best, the quality of copper core determines the transmission performance of the network cable, the higher the purity and coarser the copper, the higher the conductivity, the smaller the signal transmission attenuation. The copper wire with thick wire diameter, glossy, soft and tough is a good copper wire, and the core of the poor mesh wire is made of copper-clad steel, copper-clad aluminum, etc.
Identification method: the most direct method is weighing, whether it is wire diameter shrinkage, line length shrinkage, the use of recycled copper, copper-clad aluminum, copper-clad steel and other means of cutting corners, will directly lead to a decrease in the gram of the network cable. Weak current Jun gave a comparison table of the grams of pure copper, copper-clad steel, and copper-clad aluminum network cables:
2. Mesh cable plastic skin
Good network cable adopts new environmentally friendly plastic, safe flame retardant, flexible and bending resistance, anti-aging; Poor quality network cables often use recycled materials, which are easy to break and have a dull color.
Good network cable adopts new environmentally friendly plastic, safe flame retardant, flexible and bending resistance, anti-aging; Poor quality network cables often use recycled materials, which are easy to break and have a dull color.
Identification method: poor network cable, obviously there will be a pungent smell of recycled plastic; A good network cable basically has no taste. Good quality network cable, how to fold the outer skin will not have too obvious white, poor skimming back will see obvious white, good outer skin network cable in the comprehensive wiring construction process is not easy to break. A good mesh cable skin is flame retardant, and after lighting a short section with a lighter, the fire will be extinguished immediately, and the defective product will continue to ignite.
3. Twisting distance
The so-called twisting distance of the network cable is actually the length of the network cable button, usually people use the twisting distance to indicate the tightness of each pair of wires intertwined, the twisting control is tight, accurate, can effectively offset the signal crosstalk between the line pairs, while better resisting the external electromagnetic interference, to ensure the stability of signal transmission.
Identification method: A good network cable is not only tightly and evenly twisted in two pairs, but also tightly and evenly twisted together between the four sets of wires. The regular brand network cable is full and tight, and the network cable is basically stranded into a regular thread, while the inferior network cable has a smooth skin without any grain.
The summary identification methods are as follows:
1. Identification identification: the identification of the five-category line is CAT5, the identification of the super-five-category line is CAT5E, and the identification of the six-category line is CAT6.
2. Feel by hand: high-quality network cable generally uses copper wire as the wire core, relatively soft, inferior wire adds other metal elements, relatively hard, not easy to bend, easy to break the wire in use.
3. Cut with a knife: remove the plastic skin to expose the core wire, the white core wire is white, the fake is usually pure white or the color is not obvious, the good mesh wire winding density is uniform and moderate, and the direction is counterclockwise.
4. Burning with fire: with high temperature test, the rubber skin outside the genuine network cable will not become soft, the rubber outside the real network cable has flame retardancy, while some fake ones are not flame retardant.
Post time: Jul-24-2023