This is a RoHS compliant optocoupler manufactured by Lite-On, which combines a four-pin SOP-4 package and a LTV-217TP1-B-V-G circuitry. The circuitry is a compact integrated circuit-based optocoupler, in which the electrical insulation between its input and output terminals is achieved by the use of a light-emitting diode (LED) and a light-detecting element. The LTV-217TP1-B-V-G is typically used to isolate and transfer electrical signals from one side of the circuit to the other while providing a high degree of electrical isolation and providing protection for both the user and the circuit. It is ideal for applications where relatively low power isolation is required between circuits of different voltage levels, and it is especially useful in providing noisy interference protection to high-frequency data and digital control systems.