CK,
There isn't much going on in the program just some serial port forwarding and checking some IO. I only went with it to have access to a second high speed serial port. The uno I am trying to interface with is built into a custom board that doesn't allow easy access to the rx/tx pins or any other pins for that matter. 3018 CNC control board. If I could implement a usb host solution I could have access through the usb port. Unfortunately I have no idea how USB protocols work....