A telephone line is the incoming line of a telephone, which is connected to the telephone in order to make a call. It is divided into 2 cores and 4 cores. The conductor materials are divided into three types: copper clad steel, copper clad aluminum, and all copper, with all copper having the best conductor effect.
Explain
1. Product execution standards: refer to the YD/T630-93 standard of the Post and Telecommunications Bureau and the Enterprise Standard of Endeavour;
2. Insulation material: high-density polyethylene or polypropylene, with the color of the insulation wire marked according to the national standard chromatography;
3. Insulation pairing: Twist a single insulation into pairs according to different pitches, and use a specified chromatographic combination to identify wire pairs, reducing mutual interference and crosstalk between leads, and reducing power consumption