OST1MA3131A is a 5 mm optocoupler module from Optosupply Co., Ltd. It is designed for applications requiring non-contact signal isolation, such as isolation from high voltage or noise control. The module features an integrated LED light source, a Hall element, a phototransistor, and a buffer. It is also capable of speed sensing, pulse width modulation, and other specialized signal processing techniques. The module is UL recognized, RoHS compliant, and rated up to 6500 Vrms.