As a part of the integrated wiring design and construction, the network cable is the basic medium of most information transmission systems. Its importance is self-evident. What is the main role of the shielded network cable in this paper? What is a twisted pair? What are STP, SFTP, UTP, FTP, and ASTP? What is the super five double shielded network cable? What is the Super Category 5 single shielded cable? How to distinguish between dual-screen cable and unshielded cable, what is the difference between the two? How to distinguish the super five line? How to distinguish super six types of lines?
What is the main role of the shielded network cable?
The shielded network cable is mainly for an environment with strong interference. The environment with interference will cause the transmission signal of the network cable to be intermittent or even interrupted, and the signal cannot be transmitted normally. The use of shielded network cable can resist interference well, maintain normal transmission, and has good security performance. The shielding structure of shielded wiring has inherent advantages in reducing mutual interference between cables, and can not only shield external electromagnetic signals, but also aluminum foil. The electromagnetic leakage of the cable itself is blocked, and the interference signal is not transmitted to affect the work of other cables, and the information can be prevented from being eavesdropped.
In the shielded network cable, there will be a copper wire, that is, the ground wire. A shielded RJ45 socket can be used. When used, one end of the drain wire is grounded. The ground wire can better shield the external signal. The shielded network cable needs good grounding, and the shielded circuit can reduce the influence of strong interference on the network signal. If it is not necessary, do not use the shielded network cable. Because the wiring of the shielded network cable is high, not only the accessories in the system are required. Shielded and well grounded to function. 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, grounding noise will be generated, that is, a potential difference will be generated at some two points of the transmission channel, so that an interference current is generated on the metal shielding layer, and the shielding layer itself A maximum interference source is formed, and the wiring requirements of the shielded network cable are relatively strict. All the accessories need to have shielding performance, and a good grounding system is required. In actual construction, it is difficult to completely ground all the way, so that the shielding layer itself becomes the biggest source of interference, and the performance may not even be as good as the unshielded twisted pair.
What is a twisted pair? Why do you want to twist?
(1) Twisted pair: As a transmission medium, it is formed by winding two thin copper wires covered with an insulating material at a certain ratio.
(2) Why do you want to twist the two wires together: because this intertwining changes the original electronic characteristics of the cable, which not only reduces its own crosstalk, but also prevents the signals on other cables from being on the line. Interference on the cable.
The picture shows a super five twisted pair, consisting of four pairs of twisted pairs, a total of eight lines. Twisted pair is a kind of transmission medium which is the most commonly used transmission medium in integrated wiring engineering. It is a kind of universal wiring which is made up of two mutually insulated wires entangled with each other according to certain specifications, and belongs to the transmission medium of information communication network.
STP, SFTP, UTP, FTP, ASTP distinction
STP: Independently shielded twisted pair, adding aluminum foil layer outside the core wire, 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 wire packs, which has reached the structural standard of the seven types of cable. Applicable to high-speed network and high-secure transmission, it can support future application updates, can be unified wiring platform, and a variety of media information can be transmitted together.
SFTP: double-shielded twisted pair, adding woven mesh to STP aluminum foil, usually with aluminum-magnesium wire mesh, tinned copper mesh, outer layer is PVC outer cover, in general, there are two layers of shielding layer, and There must be insulation between the two shields. Its advantage is to effectively reduce the environmental magnetic field, signal interference, and low attenuation of internal signals. The disadvantage is that the flexibility is poor and expensive. This wire with anti-interference and high-secure transmission is suitable for professional wiring projects in special environments.
UTP: Unshielded twisted pair cable, which is the most widely used wiring system wire in the general market. It is used for general network applications with transmission bandwidth below 250MHz and no special performance requirements. The overall performance meets the requirements, the price is cheap, construction and maintenance. Convenience. However, the highest performance limit of this type only supports the cabling system of the six types of network cables.
FTP: It is an aluminum foil shielded twisted pair cable, which has the advantages of large bandwidth, certain anti-interference ability, reduced signal attenuation, low smoke and halogen free, and environmental protection.
ASTP: The armored twisted pair shielded cable (cable) is a special double shielded cable. On the basis of the above double shielded wire, the outer layer is a steel tape armor layer. When used, the steel tape armor layer is used at both ends. Ground, the innermost shield is grounded at one end. In addition to the double shielded wire effect, the strength is high, and it can be used for wiring systems with frequent rat or explosion-proof requirements. Generally, the shielded wire is more expensive and less expensive than the unshielded wire, and the bending performance is slightly poor. But it is suitable for some special environment and screen system integrated wiring. You can make reasonable choices after optimizing your situation to optimize cost and wiring.
What is the Super Category 5 single shielded network cable?
Super five types of single-shielded network cable requirements The entire system is shielded equipment, including network cables, modules, crystal heads and so on. Compared to the super five unshielded network cables, except for the twisted pair and the filling rope, the outer layer is wrapped in aluminum foil to reduce radiation. The environment used, such as severe electromagnetic radiation and strict data transmission requirements, can be trusted by the Super Category 5 single-shielded cable.
What is the super five double shielded network cable?
The double-shielded network cable is wrapped with a layer of aluminum foil outside the twisted pair and has a metal woven mesh for high-speed network and high-secure transmission to reduce radiation. This shielded wire is suitable for the application field of high-frequency signal sine wave signals, 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?
Shielded cable refers to a network cable with a shield inside. The shield refers to aluminum foil and woven mesh. The shielding layer of the single shielded network cable has only one layer of aluminum foil paper. The double shielded network cable is wrapped with a layer of aluminum foil outside the twisted pair and has a metal woven mesh. The double screen network cable and the unshielded network cable are distinguished according to the environment used. The double-shielded network cable is mainly used in an environment with strong interference, and the unshielded network cable is used in a normal daily network environment.
(1) Double shielding: The network cable and the unshielded network cable are very easy to distinguish from the internal structure. The double shielded network cable has a metal shielding mesh and a layer of aluminum foil inside, and the double shielding network cable is also called a dual screen with a network cable. There are only 4 pairs of network cables inside the non-shielded network cable.
(2) Network cable: The internal wire pairs are tightly wound in a counterclockwise direction. The method of winding the two wires together is beneficial to reduce internal crosstalk and reduce external interference. In the ordinary network environment, weak electromagnetic interference It does not affect the unshielded network cable. The core inside the cable is wound by two or two. The twist of the cable refers to the length of the twisted section of the inner twisted pair, which is used to indicate that each pair is mutually The tightness of the winding.
Each pair of wire pairs inside the network cable is twisted in a counterclockwise direction, and the twist pitch of each pair is different. This mutual winding changes the original electronic characteristics of the cable and can resist some external electromagnetic interference. It can be used to reduce the crosstalk problem caused by its own signal.
When there is strong interference in the wiring environment, it will affect the transmission effect of the network, which will lead to the interruption of the transmission signal. When the wiring environment has high-voltage wires or high-current lines of audio equipment, the network transmission signal is unstable. In this case, a double-shielded network cable is used to shield the signal of strong interference to keep the signal transmitted by the network normal.
(3) Double-shielded network cable: It is more complicated than the unshielded network cable in the process of wiring. All the accessories in the wiring system are required to have shielding performance, and a good grounding system is needed. If the grounding is not good, The shield is instead the largest source of interference, resulting in performance that may not even be as good as unshielded twisted pair, so shielded cables are used when necessary.
How do you know the Super Category 5 line?
(1) CAT 5e is printed on the super five-line body.
(2) The color of four pairs of twisted pairs in the line skin are: blue, blue and white, orange, orange, white, green, green and white, brown, brown and white.
(3) Indoor cable The same in-line and twisted pair cable is a rope (floc), which is simply used to improve the tensile strength of the cable.
The super five types of network cables are divided into unshielded network cables and shielded network cables. The difference is that the shielded network cables are divided into single shielded network cables (wrapped twisted pair of aluminum foil paper) and double shielded network cables (added a layer on the basis of aluminum foil paper). Network), the shielded network cable can effectively organize the electromagnetic radiation interference of other high-power wires and strong power supplies, greatly reduce the bit error rate of signal transmission, and play the role of shielding interference.
The materials of the super five types of network cables are divided into various types: oxygen-free copper, bronze, copper-clad aluminum, copper-clad silver, and four-iron four-aluminum. Among them, four iron and aluminum are among the worst. Copper-clad aluminum and copper-clad aluminum are burned immediately in case of fire. After burning, the bronze is also called copper-clad copper. The outer layer is covered with a layer of oxygen-free copper. The color and surface of the surface are scraped. different. Oxygen-free copper is truly oxygen-free copper, no matter how many layers are scraped and the color of the copper core does not change.
In fact, the super five types of cable have 4 pairs of twisted pair and filled rope and skin combination. The outdoor has a layer of PE waterproof outer layer, which is mainly used to protect the water and moisture. The life of the super five network cable is about 10 Around the year, if the indoor cable is used outdoors, the life expectancy is more than one year, and it can be used for a short period of time.
How to distinguish super six types of lines?
1, look at the structure
The cross skeleton, the six-category line, has an insulated cross skeleton in the middle of the super five-type line, and the four pairs of twisted pairs of the network cable are respectively placed in four grooves, such a structure can improve the balance characteristics of the cable. Compared with the five types of lines, the performance of the six types of lines is fast and stable.
2, outside watching
The line of the Category 6 line is printed with the CAT 6 logo, while the line of the Super Category 5 line is printed with CAT 5, and the copper core of the Category 6 line is thicker, which is larger than the body of the Category 5 line.
An important difference between Category 6 and Category 5 is that it improves performance in terms of crosstalk and return loss. In fact, the biggest difference between Category 5 and Category 5 is that the Category 5 line has a large performance. Lifting, the Category 5 line does not have a tensile cord.