Shielded cabling system originated in Europe, it adopted a balanced twisted pair of strands and metal shield layer shielding effect, effectively prevent electromagnetic interference signals from outside intrusion and from inside the cable leakage of electromagnetic radiation, has a very good electromagnetic compatibility features and confidentiality. Each pair shielded cable line or four pairs of wire can be used alone metal shield, metal shield layer due to skin effect and the reflection and absorption can be better separated and the reduction of electromagnetic field around the shield on a separate line, or between four pairs of wire of crosstalk between.