Introduction: Times have changed, the development of communications equipment is also advancing by leaps and bounds, from the original telephone dial-up Internet access to the current wireless WIFI, everyone's use is more and more convenient and faster, but I do not know if you reuse these signals at the same time have not noticed that after a certain distance the signal is getting weaker and weaker, and sometimes even search for the source of the signal, which is related to the Behind the scenes workers twisted-pair characteristics, today I will talk about shielded twisted-pair transmission distance and the difference between it and unshielded twisted-pair.
First and everyone popularized the knowledge of twisted-pair cable it, first take a simple example of the physical bar, usually we use the telephone line, the Internet is the most popular twisted-pair cable. With the most intuitive way of expressing the introduction of twisted-pair cable is by two wires in accordance with a certain distance winding into a line. Conductors are generally composed of copper wires, two copper wires so that winding can then reduce the surrounding signal interference to a certain extent, twisted-pair cable is generally divided into unshielded twisted-pair cable and shielded twisted-pair cable. The division of these two categories mainly depends on whether there is a metal shield between the wire and the insulating jacket, some are shielded twisted pair.
Shielded twisted-pair transmission distance
A single shielded twisted-pair transmission distance is 100 meters, if not enough for you to use, then you need to install repeaters between each two sections of twisted-pair, but not unlimited connectivity, the entire line can be installed up to four repeaters, that is, you can connect five wires, the line is 500 meters. The total length of the line is 500 meters, from another point of view, shielded twisted pair transmission of the "maximum" distance is 500 meters.
Shielded twisted pair and unshielded twisted pair difference
Shielded twisted pair and unshielded twisted pair has been very controversial, I also analyze the difference between these two types of wire.
Resistance to electromagnetic means: shielded twisted pair, the use of metal compartments within the line on the electromagnetic reflection, absorption to achieve the shielding effect.
? Unshielded twisted pair, according to its own balance to resist interference.
Applications: shielded twisted pair, military, government departments, transportation and other places that require high transmission speed and strict confidentiality.
Unshielded twisted-pair cable, generally used in ordinary business buildings, neighborhoods and other suitable for ordinary environment.Installation requirements: shielded twisted-pair cable, the installation of all connectors and accessories are required to have a shielding function and must be grounded.
? Unshielded twisted pair, no special installation requirements.
Shielded twisted pair briefly play a shielding role in the working principle
Shielded twisted pair type is generally divided into F/UTP, U/FTP, S/FTP, SF/UTP, etc., the name of the name of the slash before the total shielding layer, after the slash of the twisted pair of individual shielding layer, S refers to the wire mesh (generally copper wire mesh), F refers to aluminum foil, U refers to no shielding layer. U refers to the unshielded layer. Currently the most used Category 5, Ultra Category 5 line is basically F/UTP (aluminum foil total shielding shielded twisted pair), that is, in the eight core wire outside, sheath inside a layer of aluminum foil, in the conductive surface of the aluminum foil laid a grounding conductor.
The role of the shield is simply the use of metal on the electromagnetic wave reflection, absorption and skin effect principle (the so-called skin effect refers to the distribution of the current in the conductor cross-section with the frequency of the conductor surface distribution of the rising tendency, the higher the frequency, the smaller the depth of skinning, i.e., the higher the frequency, the weaker the penetration ability of electromagnetic waves), effectively preventing the external electromagnetic interference into the cable, and at the same time also stop the internal signal radiated out, interfering with the work of other equipment.
It should be noted that shielded twisted-pair cables only work when the entire cable is shielded and properly grounded at both ends. Therefore, it is required that the entire system be fully shielded, including cables, jacks, crystal heads and patch panels, and that the building have a good grounding system.
Shielded Twisted Pair Cable Applicable Places
Shielded cabling system should be used in semi-industrial and industrial environments
Industrial and mining enterprises are recommended to use shielded cabling system
Transmission bandwidth of more than 500MHz, or when you need to support the application of 2.5G/5G, 10GBASE-T and so on
< p>Shielded cabling should be given priority when video and audio sources are involvedShielded cabling can be considered for classified information transmission
Shielded cabling is recommended for complex environmental interference sources
Shielded cabling can be considered for certain subsystems in the weak power network
Horizontal subsystems in the data centers can be considered for shielded cabling systems
Medical buildings should use shielded cabling in critical areas
Shielded system grounding
The use of shielded cabling must meet two conditions: "the entire shielding" and "shielding layer correct and reliable grounding ". Full shielding, that is: wiring system used in the distribution frame, cables, connectors, patch cords, network equipment are shielded products, and shielding layer should be maintained between good connection and grounding. For shielded integrated wiring system, the main two ends of the ground, that is, at both ends of the shielded twisted pair cable (work area and telecommunications between the distribution frame) are grounded. In the work area of the shield of the information socket does not do special grounding, the work area through the shielded jumper will be shielded information sockets and shielded network equipment shield connection, naturally through the PE terminal of the power cord of the terminal equipment to achieve grounding. Comprehensive wiring system grounding resistance should not be greater than 4 Ω. Directly related to the shielded wiring system grounding design is mainly concentrated in the distribution frame/cabinet side, the work area shielded information outlets do not need to be connected to the equipotential bonding terminal block through the grounding entity. The reason is that the cabinet in the installation site has completed the equipotential bonding, both ends of the network equipment can be completed through the AC power supply protective earth (PE) equipotential bonding,? So that the work area shielded information outlets through the shielding jumper and equipment power PE line connected to complete the grounding. Grounding should be considered in the feeder room, telecommunications room, rack/cabinet in the room, the cabinet grounding should be connected to the equipotential bonding conductor
In summary, when the need to install the area around the strong electromagnetic interference, you should choose shielded twisted-pair cable. If it's just for ordinary residential use then unshielded twisted-pair is functional enough. Choose the right line to create a safe life, I hope this article can solve your problem for you.