The common specifications of telephone lines are two-core and four-core, with diameters of 0.4 and 0.5 respectively, and 0.8 and 1.0 in some areas. In addition to two and four cores, there are four, six, eight and ten cores. In general, if the household is in the local mode, 2 cores are enough. If it is used by the company or some group phones, considering the need for broadband use, it is recommended to use 4-core telephone lines. If it is used by digital phones, it is recommended to use 6-core telephone lines.

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.