Already made for you, and includes software:
HD Radio Cables READY!
Hello, is there a circuit available to make a serial cable interface for the HDZ300? I have made control cables for ham radios but wonder if anyone has a homemade circuit/diagram that I can follow?
i took my cable apart and it is definately not a simple wire to wire, pin to pin connection.. there are some components in there.. I would just buy it from Mitch....