Hello, welcome to Jiexi Kunlian Cable Co.,Ltd In this article, we are going to discuss some simple knowledge of the lan cable category3 (cat3), category4(cat4),category5(cat5) and category5 super(cat5e).
With the introduction and implementation of the Fast Ethernet standard, Category 5 twisted-pair cables have begun to be widely used in network cabling. However, due to the misleading propaganda of individual manufacturers and network companies, and the lack of necessary understanding of relevant standards by some network users, it is difficult to distinguish between true and false when selecting Category 5 twisted-pair cables, and they are at a loss. However, once a Category 5 twisted pair that does not meet the standard is selected, on the one hand, the overall performance of the network will decrease, and on the other hand, it will bury hidden dangers for future network upgrades. This article combines technology and application to introduce the correct identification method of standard five types of twisted pair.
In order to let everyone have a more comprehensive understanding of twisted pair, we first introduce the common types and characteristics of twisted pair. Twisted pair cables in computer local area networks can be divided into two categories: unshielded twisted pair (UTP) and shielded twisted pair (STP): STP is wrapped with a layer of metal material to reduce radiation and prevent information from being eavesdropped. It has a higher data transmission rate, but the price is higher, and the installation is more complicated; UTP has no metal shielding material, only a layer of insulating rubber wrap, the price is relatively cheap, and the network is flexible. Except for some special occasions (such as severe electromagnetic radiation, high requirements for transmission quality, etc.) when using STP in wiring, we generally use UTP. The UTP currently in use can be divided into four categories: category 3, category 4, category 5, and category 5 super. Among them: Type 3 UTP meets the requirements of Ethernet (10Mbps) for transmission media, and is an important transmission medium in the early network; Type 4 UTP is later than Type 3 due to the introduction of the standard, and the transmission performance is not compared with Type 3 UTP. How much to improve, so it is generally used less; Category 5 UTP has become the preferred medium for fast Ethernet (100Mbps) due to its low price and high quality; Category 5 UTP is used in Gigabit Ethernet (1000Mbps). According to the actual needs of the current network wiring, this article mainly introduces the correct identification and selection methods of the five types of UTP.
Speed transfer of the Cat5 or Cat5e
The quality of the twisted pair is a key factor in determining the winding. Some manufacturers twist the pair of Category 3 or Category 4 UTP in the Category 5 UTP cable. The general method is to use a twisted pair to connect two 100Mbps equipment (network card to 100Mbps equipment). Network card or network card to HUB), use the monitoring and detection tool that comes with Windows 95/98 to monitor its data transmission rate during communication. The method is: ①Select “Start→Program Accessories→System Tools→System Communication”, and the “System Intelligence” window will appear. If there is no “System Intelligence Tool” in the “System Tools” to delete the program, you can create it through My Computer→Add→Windows Installer→System Tools→System Intelligence”. ②Set the monitoring object in the “System” window. Select ” The “Add Item” option in the Edit menu selects “Microsoft Network Server” or “Microsoft Network Client” in the “Category” list of the dialog box that appears (note: under the condition that the network connection is normal), in the next dialog box Select “Bytes Written/sec” or “Bytes Read/sec”. As for choosing “Microsoft network server” or “Microsoft network client”, or “bytes written/sec” or “bytes read/sec”, readers can choose arbitrarily, because a node in the network sends out The data should be equal to the data received by another node. ③Set the output mode of test data. The system provides three output modes: line graph, bar graph and digital graph, which can be selected through the buttons in the window toolbar. ④ Perform a test. The most effective way is to copy a large number of files from the server to the workstation where you are testing (for the accuracy of the test, the copied content must be enough). Generally speaking, if the displayed peak value is above 4M/s, it is basically a five-category network cable (the peak value that can be achieved by a category 3 line is about 2.5M/s).
For the network cable the twisting of the twisted pair in the cable should meet the requirements
In order to reduce signal interference, each wire pair in a twisted-pair cable is formed by two insulated copper wires twisted with each other, and different wire pairs in the same cable have different degrees of twist (that is, the twisted coil What is the quantity), as shown in Figure 3. At the same time, the wire pairs in standard twisted-pair cables are twisted in a counterclockwise direction. However, the cables produced by some informal manufacturers have many problems: ①In order to simplify the manufacturing process, the twisting density of all wire pairs in the cable is the same; ②The twisting density of the two insulated conductors in the pair does not meet the technical requirements; ③ The twisting direction of the wire pair does not meet the requirements. If the above problems exist, it will cause near-end crosstalk (referring to the signal interference between two pairs in UTP) of the twisted pair, so that the transmission distance cannot meet the requirements. The twisting degree of the twisted pair has strict standards in the production. In the actual purchase, some professional equipment can be used to measure it under conditions, but the general user can only observe it with the naked eye. It should be noted that the twisting degree of the wire pairs in the five types of UTP is better than that of the three types, and the super five types are better than the five types.
In addition to the two insulated copper conductors that make up the twisted-pair wire pair, they must be twisted as required, and the wire pairs in the standard twisted-pair cable must also be twisted in a counterclockwise direction. Otherwise it will cause mismatch of cable resistance and limit the transmission distance. This is rarely noticed by the average user. For the twisting degree and other related parameters of Category 5 twisted-pair cables, interested readers can refer to TIA/EIA 568A (TIA/EIA 568 is a wiring standard formulated by ANSI in 1996. Infrastructure, including cables, connecting equipment, etc. The letter “A” represents the IBM wiring standard, while AT&T uses the letter “B” to represent the specific provisions in)
(in the next article, we will discuss how to choose good quality cat5e cable from the mass cable market)