Shielded twisted cable
has a metal shielding layer between the twisted cable and the outer insulating sheath. Shielded twisted cable is divided into STP and FTP (Foil Twisted-Pair). STP means that each line has its own shielding layer, while FTP only works when the entire cable has a shielding device and both ends are correctly grounded. Therefore, the entire system is required to be shielded devices, including cables, information points, crystal heads and distribution frames, etc. At the same time, the building needs to have a good grounding system. The shielding layer can reduce radiation, prevent information from being eavesdropped on, and prevent the entry of external electromagnetic interference, so that shielded twisted pair cables have a higher transmission rate than similar unshielded twisted cables. However, in actual construction, it is difficult to perfectly ground all of them, so that the shielding layer itself becomes the largest source of interference, resulting in performance that is far inferior to that of unshielded twisted cable
. Therefore, unless there are special needs, usually only unshielded twisted cable is used in the integrated wiring system.
Unshielded twisted cable
(abbreviated as UTP) is a data transmission line composed of four pairs of transmission lines of different colors, which are widely used in Ethernet circuits and telephone lines. Unshielded twisted cable has the following advantages: 1. No shielded jacket, small diameter, saving space and low cost; 2. Light weight, easy to bend, and easy to install; 3. To minimize or eliminate crosstalk; 4. .With flame retardancy; 5. With independence and flexibility, it is suitable for structured integrated wiring. Therefore, in the integrated wiring system, unshielded twisted pair is widely used.