Help using an optocoupler for parallel port data input

[wkehr]

optocoupler parallel port

Doing a search for parallel port and optocoupler brings up lots of information about using optocouplers to isolate a PC parallel port when the PC sends out data (often to transistors controlling relays). Unfortunately, I don't find examples of using an optocoupler to isolate the port when doing data acquisition. Has anyone done this who can give examples?

Does the parallel port have enough current to make this work? I would suspect yes because there are circuits showing the parallel port driving several IC's.

 

[shawan44]

parallel port optocoupler

u can use transistor & relay with out using optocouplers i used it it works use 1k resister between output of parallel port & transistor base, use relay(&reverse biased diode) between supply & collector,connect emitter on ground.

u can use any transistor (npn type) or diode i used c828 transistor & 1n4001 diode