LBD-A/V signal isolator is used in the automatic control system, to each industry signal the transformation, the isolation, the transmission, the operation measuring appliance, with supporting the use of a variety of industrial sensors, to obtain the signal parameters, and isolate changes delivers the transmission. Widely applies in the machinery, the electricity, the telecommunication, the electric power, the sewage treatment, domain and so on building construction data acquisitions, the signaling transforms, industry observation and control systems and so on PLC, DCS, use for to consummate and the supplement system simulation I/O plug-in unit function, the increase system serviceability and the scene environment margin of safety.