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.

The copper-clad steel telephone wire is relatively hard and is not suitable for external cable pulling, which is easy to break the core. But it can still be used if buried in the wall. It can only be used in close range. The telephone line made of imported polypropylene material has high purity, lower transmission attenuation and higher transmission speed. It is suitable for broadband internet access and can meet the requirements of high transmission speed of videophone.