As a part of the integrated wiring design and construction, the network cable is the basic medium for most information transmission systems. Its importance is self-evident. What will be the main functions of the shielded network cable? What is the twisted pair? STP, SFTP, UTP, FTP, ASTP and what are they? What kind of super five double shielded cable? What is a super five single shielded cable? How to distinguish between dual screen cable and non-shielded cable, what is the difference between the two? How to distinguish Super five line? How to Resolve Super Six Line?
What is the main role of shielding network cable?
Shielded network cables are mainly used for environments with strong interference. Interference-prone environments can cause network cables to transmit signals intermittently or even interrupted and cannot transmit signals properly. The use of shielded network cable can be a good resistance to interference, to maintain normal transmission, and has a good security performance, shielded wiring shielding structure to reduce the mutual interference between cables has innate advantages, not only can shield the external electromagnetic signal, aluminum foil also at the same time The electromagnetic leakage of the cable itself is blocked, and interference signals do not affect the work of other cables, which can prevent the information from being intercepted.
In the shielded network cable, there will be a copper wire, that is, a ground wire. A shielded RJ45 socket may be used, and one end of the drain wire is grounded during use. The ground wire can better shield external signals. Shielded network cables need good grounding, and shielding circuits can well reduce the influence of strong interference on network signals. In non-essential cases, do not use shielded network cables because the requirements for the shielding of network cables are high, and not only the parts in the system are required. With shielding, and to have a good grounding to play a role. If the grounding is not good, the effect will be very poor.
If the grounding point is not arranged correctly, the grounding resistance is too large, or the grounding potential is not balanced, ground noise will be caused, that is, a potential difference will occur at some two points of the transmission channel, so that the interference current will be generated on the metal shielding layer. At this time, the shielding layer itself The largest source of interference is formed, and the wiring requirements of shielded network cables are relatively stringent. All accessories are required to have shielding performance and a good grounding system is required. In the actual construction, it is difficult to perfectly ground all, so that the shield itself becomes the largest source of interference, resulting in performance may not even be better than unshielded twisted pair.
What is twisted pair? Why twisted?
(1) Twisted Pair: As a transmission medium, it is made up of two fine copper wires wrapped with insulating material and entangled with each other at a certain ratio.
(2)Why twist two-wire twisting?Because this mutual winding changes the original electronic characteristics of the cable, this will not only reduce the self-crosstalk, but also can prevent the signal on the other cable from reaching the line as much as possible. Interference on the cable.
The picture shows a Category 5e twisted pair consisting of four pairs of mutually intertwined pairs of eight wires. Twisted pair is a kind of common transmission medium used in the integrated wiring project. It is a kind of universal wiring made of two mutually insulated conductors that are intertwined with each other according to certain specifications and belongs to the information and communication network transmission medium.
STP, SFTP, UTP, FTP, ASTP distinction
STP: Independent shielded twisted pair, aluminum foil layer is added outside the core, each pair of wires has an aluminum foil shielding layer, in order to reduce signal attenuation. There is also a metal braided shield for every 4 pairs of cords, which has reached the structural standard for seven types of cords. Suitable for high-speed networks and high confidentiality transmission, it can support future application updates, can be a unified wiring platform, and a variety of media information can be transmitted together.
SFTP: Double-shielded twisted pair cable. The braided net is added to the aluminum foil of STP. Usually, aluminum-magnesia-wire braided wire mesh, tin-plated copper mesh are used, and the outer layer is PVC covered. Generally, there are two layers of shielding layers. There must be insulation between the two shielding layers. Its advantage lies in effectively reducing the environmental magnetic field, signal interference, and the internal signal attenuation is low. The disadvantages are poor flexibility and high cost. This kind of wire with anti-interference and highly confidential transmission is suitable for special wiring projects in special environments.
UTP: Unshielded Twisted Pair, this type is currently the most widely used cabling system wire in the general market, is used for transmission network bandwidth below 250MHz, general network applications without special performance requirements, overall performance meets requirements, cheap, construction and maintenance Convenience. However, the highest performance limit of this type only supports the cabling system of the Category VI network cable.
FTP: aluminum foil shielded twisted pair, which has the advantages of greater bandwidth, certain anti-interference ability, reduced signal attenuation, low-smoke halogen-free recovery, and environmental protection.
ASTP: armored twisted-pair shielded cable (cable) is a special double-shielded cable. On the basis of the above double-shielded cable, the outer layer is a steel tape armored layer. When used, both ends of the armored armored layer Grounding, one end of the inner shield is grounded. With the effect of double shielded wire, the strength is higher. It can be used in the wiring system where the rodent damage is frequent or has explosion-proof requirements. Generally, the shielded wire is more expensive and more expensive than the non-shielded wire, and the bending performance is slightly inferior. But it is suitable for some special environment and screen system integrated wiring. Everyone can make reasonable choices after understanding their own situation and optimize the cost and wiring effect.
What is a super five single shielded cable?
Super five single shielded cable requirements The entire system is all shielding equipment, including cable, module, crystal head. Compared to the Super Category 5 unshielded network cable, except for the twisted pair and the filler string, the outer layer is covered by aluminum foil, which can reduce radiation. If the environment used is severe, such as electromagnetic radiation, and data transmission requirements are stringent, ultra-quinaline single-shielded network cables can be trusted.
What is a super five double shielded cable?
The double shielded cable is wrapped with a layer of aluminum foil on the twisted pair, and has a layer of metal woven mesh, which is suitable for high-speed networks and high confidentiality transmission to reduce radiation. This kind of shielded wire is suitable for the application field of the high-frequency signal sine wave signal, and is applied to the wiring between the user communication terminal of the residential integrated wiring system and the distribution frame.
How to distinguish between dual-screen cable and unshielded cable?
A shielded cable refers to a shielded cable, and a shield refers to an aluminum foil and a braided cable. Single-shielded cable shield only one layer of aluminum foil, double shielded cable wrapped in a twisted pair of aluminum foil, and a layer of metal braided mesh, dual-screen cable and unshielded cable is based on the use of different environments to distinguish Dual-shielded network cables are mainly used in environments with strong interference, and unshielded network cables are used in common everyday network environments.
(1) Double shielding: The internal structure of the network cable and the unshielded network cable is very easy to distinguish. The double-shielded cable has a metal shielding network and a layer of aluminum foil. The double-shielded network cable is also called the dual-screen network cable. There are only 4 pairs of network cables inside the non-shielded cable.
(2) Network cable: The internal cable pairs are tightly twisted together in counter-clockwise direction. Pairwise entanglement helps to reduce internal crosstalk and reduce external interference. In an ordinary network environment, weak electromagnetic interference occurs. The non-shielded cable does not affect the cable. The cable inside the cable adopts a pair of winding method. The cable twisting distance refers to the length of the twisted pair of the inner cable pair. The length of the twisted pair is used to indicate each pair of cable pairs. The tightness of the winding.
Each pair inside the cable is twisted counterclockwise, and the twisting distance of each pair is different. This mutual winding changes the original electronic characteristics of the cable and can resist part of the external electromagnetic interference. It can be used to reduce crosstalk caused by its own signal.
When the wiring environment has strong interference influence, it will affect the transmission effect of the network. Severely, it will cause the transmission signal to be interrupted. When the wiring environment has high-voltage wires or strong current lines of audio equipment, the phenomenon of instability of the network transmission signal is more obvious. In this case, it is necessary to use double-shielded network cables to shield strong interference signals to keep the network transmission signals normal.
(3) Double-shielded cable: In the process of wiring, it is more complicated than unshielded cable. In the wiring system, all the accessories are required to have shielding performance, and a good grounding system is required. If the grounding system is not good, Making the shield the largest source of interference on the contrary can result in performance that may not even be as good as an unshielded twisted pair, so use a shielded network cable only when necessary.
How do you know about the super five line?
1, see
(1) CAT 5e is printed on the super five line.
(2) The colors of the four twisted pairs in the sheath are blue, blue and white, orange, orange and white, green, green and white, brown and brown.
(3) Indoor Cables In-line leather and twisted cables are also provided with a rope (flock), referred to as a tensile rope, which is used to increase the tensile strength of the cable.
2, identify
Super five cable is divided into non-shielded cable and shielded cable, the difference is: shielded cable is divided into single shielded cable (wrapped twisted pair of aluminum foil) and double shielded cable (in the aluminum foil based on a layer of code Network). Shielded network cables can effectively organize the electromagnetic radiation interference of other high-power wires and strong power supplies, greatly reducing the error rate of signal transmission and acting as a shield for interference.
3, classification
There are several types of materials for Super Category 5 cables: oxygen-free copper, bronze, copper clad aluminum, copper clad silver, and tetra-iron four-aluminum. Among them, four-iron four aluminum is one of the worst quality. Copper-clad aluminum and copper-clad aluminum are immediately burnt in the event of a fire, and once burned, they are broken. Bronze is also collectively referred to as copper-clad copper. The outer layer is coated with an oxygen-free copper layer. different. Oxygen-free copper is truly oxygen-free copper, no matter how many layers of scraped surface and copper core color will not change.
In fact, there are four pairs of twisted-pair cable, cable, and skin. In the outdoor, there is a layer of PE waterproof outer layer than the indoor, which is mainly to play the role of waterproof and moisture-proof, the life of ultra-five cable is probably 10 In the year or so, if the indoor cable is used outdoors, the service life is generally more than one year, and it can be used in the short term.
How to distinguish Super six line?
1, see the structure:
The cross-bracket and the six-type cable have more than one insulating cross-bracket in the middle of the super-five cable. The four pairs of twisted pairs of the cable are respectively placed in four recesses. This structure can improve the balance performance of the cable. Compared with the Category 5 line, the performance of the Category 6 cable is fast and stable.
2, outside watching:
The line of the Category 6 line is marked with the logo of the CAT 6, and the line of the Category 5e line is the Print CAT 5, and the copper core of the Category 6 line is thicker and larger than the line of the Category 5 line.
3, performance:
An important difference between the six categories and the super five categories is that they improve the performance in terms of crosstalk and return loss. In fact, the biggest difference between the five-category and the fifth-category is that the super-fifth line has a larger performance. Ascension, the Cat 5 line does not have a pull rope.
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