Thank you, you are brilliant. It is not the answer I was looking for, but thanks for explaining. I hope the world has more people like you who are willing to help a beginner. I want to be creative with technology, but don't want to be a engineer.

Okay, based on the documentation, 1-3 hub is a hardware extender which does not change units' addresses, only extend them. If the input units share the same addresses, they will interfere each other. The solution is to use a pBhub instead.

I realized Mini Button unit, OP 90 and 180 unit, Dual Button Unit examples are all using pin 36. Does that mean I can't use them together as separate inputs? There must be a way!

I wanted to use an OP-90 and a Dual Button Units together. I connected them to Port B on a M5 Fire through a 3 - 1 hub. I realized that they both use pin 36. Is there a way to change that? How can I use them together, many thanks!