Review on 🚀 Enhanced Performance: HiLetgo Channel Isolated Optocoupler Trigger for Optimal Signal Transmission by Evan Zurlo

That's true without a diagram, but it's very easy to understand. coil 12V; Connect DC- to ground and DC+ to 12V. The two switches have a common normally closed and normally open position and are rated for 10 amps; identified as COM1, NC1, NO1 and COM2, NC2, N02. Jumper selectable positive or negative trigger; defined as Com, High and Low. I used a high trigger so I connected the com jumper to high. If you want the com low trigger jumper to be set low. IN1 and IN2 must be 12V to switch the relay; IN1 controls relay 1 and IN2 controls relay 2. I simply connect IN1 and IN2 to 12V for my application. Note. When the DC+ 12V power is on, the green LED lights up. When IN1 is powered with 12V the red LED next to relay 1 is lit. When IN2 is powered with 12V the red LED next to relay 2 is lit. Actually I had (accidentally) left a wire unconnected to IN1 and it was immediately visible . I used 4 of these cards in my circuit so I had a few wires connected and it was easy to see my mistake because of the lights. At this time of year (December) when my circuit is activated it looks like Christmas with green and red LEDs. .