The selection of cables shall be comprehensively considered according to the system requirements, technical performance, investment budget and other factors, but in the cabling system, the category of cables and the structure of cabling (unshielded cables, shielded cables, optical cables or several kinds of mixed use) shall be determined first. Cables usually use insulated conductors and one or more layers of plastic sheath. The cable usually consists of 2 to 3600 pairs. Large pairs of cables are usually used in backbone cabling systems, and they are suitable for voice and low rate data transmission. The maximum length of these cables in trunk and horizontal (hub to desktop) cabling system applications is detailed in the latest GB50311-2007. It should be noted that these maximum length limits apply to all media. They do not consider the impact of performance differences caused by different cable types and protocol types used in the network. In fact, the maximum cable length will depend on the system application, network type and cable quality.

According to the data in the Analysis Report on the Development Prospects and Investment Strategic Planning of China's Intelligent Building Industry from 2013 to 2017, after breaking through 20 billion yuan for the first time in 2005, the market of China's intelligent building industry is also growing at an annual rate of more than 20%. In 2012, the market size reached 86.1 billion yuan. From the data point of view, intelligent buildings have developed rapidly in China in recent years, which also shows that intelligent buildings are a major trend of future building development.

Since it is a building, it will definitely use a lot of communication cables. As the nervous system generic cabling system in intelligent buildings, it is the key part and infrastructure of intelligent buildings. It is closely related to the planning, design, construction, installation, maintenance and use of building projects. It is like an information highway in the building, where people can communicate and communicate conveniently, quickly and effectively. It can be said that the generic cabling system connects the communication, computers and various facilities and equipment in the intelligent building to form a complete supporting whole to meet the requirements of high intelligence.

But then we have to consider one problem: fire prevention. Because in case of fire in the building, the heat and toxic gas released by these cables will become a major safety hazard. Looking at several large-scale fire accidents in China in recent years, many of them are due to the victims' inability to escape. The burning of cables emits toxic acid gas, coupled with a large amount of heat and smoke released by the burning, which makes it difficult for the victims to breathe, leading to tragedy. Therefore, in addition to performance, fire protection and environmental protection are also particularly important reference factors when we choose cables for the generic cabling system.