Wiring boards and plugs are commonly used connection devices in electronic equipment, and they can be divided into various types according to their uses and specifications. according to the use, it can be divided into household, industrial, medical, aerospace, etc.; according to the specifications, it can be divided into european standard, american standard, british standard, japanese standard, etc. in addition, there are terminal blocks and plugs with special requirements such as waterproof, fireproof, explosion-proof, and protective devices. these connection devices not only facilitate the connection of equipment, but also improve electrical safety.