TD1-13A series product, an invention patent product, is applied in signal protection for DCS system with hot pluggable and failure indicator functions. Adopting Extensive comments from engineers in iron and steel, petroleum, chemical industries etc, it firstly realized failure tripping technology to guarantee normal signal transmission under product failure situation. It is the ultimate surge protection solution for process equipment, I/O system and communication networks. It adopts slim space-saving design with LED failure indicator.