User:N.Brilixe/sandbox

When a fire, water damage or geological damage occurs in an underground space, the communication lines in the underground space are easily damaged and interrupted, which makes it difficult for the underground emergency contact and rescue command to be implemented. The ground communication system is applicable to the remote data anti-destruction transmission using reinforcing mesh, buried pipe network, semi-buried steel rail, drill pipe, etc. as the transmission medium. The environmental characteristics of the underground space are linear scenes, limited space, and power concentration. Any explosion and collapse or flooding under the pressure of the formation will easily destroy the underground communication lines. The expansion of people's living space, the high-paced development of underground commercial streets, underground garages, subways and railway tunnels has brought about new situations in the underground space where the environment is closed, the structure is complex, and the population is dense. How to establish an effective communication security in the event of an emergency such as a fire is the key to the current development. At present, underground space communication is based on wired communication (underground wireless network is a base station-type wired network). When the wire is damaged, it will cause disasters and lost. Earth wire communications opened the era of green and invulnerable information on the subway, making it possible for people trapped in underground space to communicate with the ground, and the telephone line is a solid rail that cannot be destroyed. These sturdy, destructive steels are special conductors that do not have to be insulated, and the other conductors are deep silt formations. The signals transmitted by the criss-crossing rails are converted into ordinary telephones, which support the interface of ordinary telephones. The existing subway broadcasting network needs to rely on the star-shaped radiation topology of the central switch. After the destruction of the central switch in the event of a disaster, the communication network will fail. However, the ground line communication is the use of pipe network, rail, cable communication, the ground line communication topology is the ring network bus structure and the corresponding token addressing mode, in the disaster environment to provide a stable telephone and broadcast systems and data services. The groundbreaking, confidential, and flexible ground communications eradicated the zero point of the scope of wireless and wired communications and the pain points in the implementation of rescue operations, and promoted the synchronization of communications to the "Metropolis era." The ground cable-free signal transmission technology is missing the technical defects of wireless communication and wired transmission. It is a subversion of traditional information technology and a revolution in communication reliability. It can play a unique role in disaster liaison, emergency rescue, disaster site command, and catastrophe prediction; it has a strong guarantee of survivability in communication security for underwater, underground, and fire environment. It has made revolutionary developments in smart homes, geological disaster prediction, and military non-electromagnetically secure communication technologies.