How to wire my relay board?

I bought this board and I want to switch the relays with the Arduino. I have a separate 12VDC power supply for the orange leads (VCC/GRD) that also is the power that the relays switch.

As I understand it there's about 3 ways to work these relays with an Arduino.

  1. use a transistor like the S8050 and have that switch from the 12V COMM to IN1..4 at the green connectors.

  2. use optocoupler

  3. (Low level trigger) use the high/low jumper settings on low and provide 5VDC from the Arduino

So far, I've had all the jumpers set to LOW and provided 12VDC to the orange leads. Use a wire from the green COM to each of the IN1..4 and it works. It's showing 12V on the green COM and I was told that if I connect that 12V to the Arduino, it would fry it.

I can't seem to find a wiring example for this board, but I'm told I can run it several ways with the Arduino.

What I don't get, is where do I apply the 5VDC from the Arduino and where do I set the jumpers?

I see some that suggest I apply the 5VDC from the Arduino to the jumper pin COM (-) and LOW (+) for which ever relay I want to switch.

I don't see any jumper setting for using the optocoupler, so I understand that the optocoupler is the best option, but don't know if it using 5VDC from the Arduino for switching.

Q1. can I switch this relay with 5VDC from an Arduino using optocoupler?

Q2. how can I use low level trigger to switch the relays with 5VDC? Where do I apply the wires? I assume that I need 12VDC for the coil in all cases, and that's supplied at the orange leads.

My assumptions are that the relay coils get their power from the 12V orange leads. What I don't understand is the jumper settings for high/low and opto and where to apply the 5VDC from the Arduino.

Links to specs sheet come up 404.

Here's a link to take a look at, but I didn't get confirmation from the OP that he used this connection scheme.

Opto Isolation Connections:

  1. Your relays use a 12V power supply, so that connects to DC+ and DC-
  2. Remove both jumpers
  3. Use the middle pin of one of the jumper headers to connect to either 5V (LL trigger) or GND (HL trigger)
  4. Connect the CH1-4 (IN1-4) inputs to Arduino
  5. In summary, there's only 5 wires connecting to Arduino ... 4 control wires and 1 power (5V or GND)

I think only the 5V method (LL trigger) offers true opto-isolation, but I would need to test one of these to know for sure if using GND and HL trigger would still offer opto-isolation.