What is a shielded twisted pair cable? What are STP, SFTP, UTP, FTP, and ASTP respectively?

1. The difference between shielded and unshielded twisted pair cables

Let's take a look at their appearance. From the appearance, we can see that the shielded twisted pair cable has a shielding layer of aluminum foil or copper braided wire inside.

There are single-layer or multi-layer shielding and independent shielding. Double shielded twisted pair cable, each pair of twisted pair has a shielding layer, and the outer layer also shares one or more layers of shielding.

Shielded twisted pair cable refers to the cable that has a shielding layer inside, which is aluminum foil and braided wire. The shielding layer of the single-shielded twisted pair cable is only a layer of aluminum foil paper, the double-shielded twisted pair cable has a layer of aluminum foil wrapped around the twisted pair, and a layer of metal braided wire, the double-shielded twisted pair cable and the unshielded twisted pair cable are distinguished according to the different environments they are used in, the double shielded twisted pair cable is mainly used in environments with strong interference, and the unshielded twisted pair cable is used in normal daily network environments.

2. The use of shielded twisted pair cable

Because of the structure of the shielded twisted pair cable, determines its use, shielding is to reduce the impact of external electromagnetic interference on data transmission, commonly used in electromagnetic environments with complex interference strong computer room environment.

The interference environment will cause the cable to transmit signal intermittently, or even interrupt, unable to transmit signal normally. Using shielded twisted pair cable can resist interference well, maintain normal transmission, and have good confidentiality performance, the shielding structure of shielded cabling has a natural advantage in reducing the mutual interference between cables, not only can shield the external electromagnetic signal, but aluminum foil also blocks the electromagnetic leakage of the cable itself, will not emit interference signal to affect the work of other cables, can prevent information from being eavesdropped. In the shielded twisted pair cable, there will be a copper wire, which is the ground wire, can use a shielded RJ45 socket, when using, the drain wire at one end is grounded. The ground wire can better shield the external signal. Shielded twisted pair cable needs good grounding, and the shielded line can reduce the strong interference to the network signal well, in the unnecessary situation, do not use shielded twisted pair cable, because the shielded twisted pair cable wiring requirements are high, not only require the accessories in the system are shielded, and must have good grounding to play a role. If the grounding is not good, then the effect will be very bad.

3. The distinction between STP, SFTP, UTP, FTP, and ASTP

STP: That is, independent shielded twisted pair cable, adding an aluminum foil layer outside the core wire, each pair of wires has an aluminum foil shielding layer, the purpose is to reduce the signal attenuation. Each four pairs of wires is also packed with a metal braided shielding layer, which has reached the structure standard of category 7 cable. Suitable for high-speed network and high confidentiality transmission, can support future application updates, can unify the cabling platform, and multiple media information transmission together.

SFTP: That is, double shielded twisted pair cable, adding braided wire based on STP aluminum foil, usually using aluminum magnesium wire braided wire, tin-plated copper wire, the outer layer is PVC sheath, the total is two layers of shielding layer, and the two layers of shielding layer must have insulation isolation. Its advantage is that it can effectively reduce the environmental magnetic field, signal interference, and internal signal attenuation degree is low. The disadvantage is that it is soft and expensive, this kind of anti-interference and high confidentiality transmission wire is suitable for special environments and professional cabling engineering.

UTP: That is, unshielded twisted pair cable, this type is the most widely used cabling system wire in the ordinary market, used for transmission bandwidth below 250MHz, has no special performance requirements of ordinary network applications, the overall performance meets the requirements, cheap, easy to construct and maintain. However, the performance limit of this type only supports the cabling system of category 6 cable. FTP: That is, 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: That is, armored twisted pair shielded cable (cable) is a more special double shielded twisted pair cable, based on the above double shielded twisted pair cable, the outer layer is the steel belt armored layer when using, the steel belt armored layer at both ends is grounded, the innermost shielding layer is grounded at one end. It has the effect of double shielded twisted pair cable, high strength, and can be used for frequent rodent damage or explosion-proof requirements of the cabling system, general shielded twisted pair cable than unshielded twisted pair cable in cost and installation will be more expensive, bending performance is slightly worse. But suitable for some special environments and shielding system integrated cabling. Everyone can choose reasonably after understanding their situation, optimize the cost and cabling effect.`