How to configure pins of photocopier optocoupler switch

There 3 pins
Vcc
Gnd
Out

How can find them correctly.
I tried with multimeter diode mode can not get a idea.

any ideas?

My best guess (without having any to test on) is that the outer two wires are VCC and GND, and the middle wire is the output.

Put the multimeter (in diode mode) across the outer two wires, and you should get a "beep" and a reading of approx. 0.7V - if not, swap the multimeter probes. Whichever wire the black/negative probe is touching when it beeps (or reads a low voltage) is the GND wire.

Try that first - come back if any further issues.

HueyHQ wrote:

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Put the multimeter (in diode mode) across the outer two wires, and you should get a "beep" and a reading of approx. 0.7V - if not, swap the multimeter probes. Whichever wire the black/negative probe is touching when it beeps (or reads a low voltage) is the GND wire.

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I don't get a reading with your method?

The other option is to put a series resistor in the 5V power lead (say 330 Ohms)
so a reversed connection will do no harm, and then try the outer leads both ways
( checking if the middle pin responds to blocking the light path )

emitter is IR?

Almost always...

Watch and tell me?