H11l1 schmitt trigger isolator isocom h11l1 u the h11l1 is an optically coupled isolator that consists of a gallium arsenide infrared emitting diode in conjunction with a microprocessor compatible schmitt trigger output the devices isolation properties along with its ability to eliminate noise and transients make it especially suitable for applications such as logic to logic isolation programmable current level sensor ac to ttl conversion isocom h11l1 schmitt trigger isolator