Wow that looks really good. I’m hoping we can get enough people to make this happen. I’d even consider buying 2 sets if it makes the difference between moving this forward or not.
Ok,
Try to simply do this, the point is to connect the 5V of the MIDI out to the 5V of the MIDI In to get the input optocoupler acting.
Works fine for me on a Polymoon, receive and send. And cabling example:
Normally the 220ohm already present in your MIDI output acts as current limiter, no need for more resistor.
Best
Bruno