TLP281 4 Channel Opto Isolator Module - ILD213T Optoisolator.Digital systems (such as 5V microcontroller) with high voltage or noise It comes with two channels that can help you connect it to a system. This optoisolator electrically isolates a controller from the high power system using an IC. This isolation board uses the TLP281 optoisolator and discrete transistors for isolation. It comes with four channels. There are four LEDs and four photodiodes built in. This allows the low voltage side to control the high voltage side. This card will isolate the systems and create a type of electrical noise barrier between devices. You can use this board to allow a microcontroller control servos or other motors that use higher voltage than TTL logic (3.3V or 5V) micro, and may cause electromagnetic interference in your system as the motors turn on and off. It can also be used in noisy circuits where signal lines require electrical isolation.