@rjenkinsgb ah I did not know that. I thought a OTG adapter would be something like a crossover ethernet cable. And with that one it doesn't matter which device sits on either end as long as there is a crossover (and even this isn't always necessary nowadays).

I will try it then with the otg Adapter on the phone and a standard micro b cable in the duet and report back.

EDIT: works

Now I only need to find wiring that fits my space constraints 😉