The 4N234N24 from ISOCOM is a Space Qualified Optocoupler with Forward Voltage 1.8 V, Continuous Current 50 mA, Collector-Emitter Dark Current 100 uA, Collector-Emitter Saturation Voltage 0.3 V, Operating Temperature -55 to 125 Degree C. Tags: Through Hole. More details for 4N234N24 can be seen below.