High-density polyethylene or polypropylene, indicating the color of the insulating wire according to the national standard chromatography; Twist the single insulation into pairs according to different pitches, and use the specified chromatogram combination to identify the wire pairs to reduce the mutual interference and crosstalk between the wires, and the power loss is small.

Telephone and internet have penetrated into the lives of thousands of households. The internet has brought us closer to each other, while telephone has promoted people's communication. The telephone cannot be separated from the telephone line, and the network cannot be separated from the network line. Most telephone lines appear as parallel lines, with two cores.