cable shielding contain ordinary insulated conductors that are encapsulated in a standard conductive layer with a special protective shield. This shield distinguishes these cables from the normal unshielded variants.
The shield is wrapped around the insulated conductors and is usually made of: Braided copper and similar metal strands Spiral copper tape Conductive polymer
What does shielded cable do?
cable shielding reduce and isolate data or power transmissions from the high power “electrical noise” or environmental electromagnetic interference (EMI) present in industrial, engineering or manufacturing environments where data and power transmissions are subject to electronic interference.
What is Electromagnetic Interference (EMI)?
EMI is the variable currents and voltages that often occur in the environment. We think of it as common interference that disrupts things like cell phones, TVs, or AM radios. It can be natural, inherent or man-made.
Naturally occurring EMI can be caused by thunderstorms and lightning storms, snow storms, rain particles and solar radiation. Natural EMI causes fewer problems for modern digital equipment than older data links and RF communications over ships, ashore and in the air.
Inherent EMI is the electrical noise generated within electronic equipment. The thermal stirring of electrons flowing through circuit resistors produces “white noise”, usually associated with the familiar sound of radio receiver frequencies between stations.
Man-made EMI is caused by different categories of electrical and electronic equipment. Vehicle ignition, motors, transmitters, generators, power lines, cell phones, lighting types, etc. are examples of man-made equipment that may cause EMI degradation in power supply systems and data processing equipment.
Vietnamese 
Thai