I figured out a way to connect the Ring Pro with the Nutone, Music & Sound, and Audiotech Intercom Systems Door Bell Chimes. My kit also will send power to your old front door speaker location. You can contact me.
Thanks, Darrell Brock (Wirenutman)
I am about to start a similar project so I can integrate my Ring Pro with my KSU (phone system/intercom). Can you tell us more about your project? Are you willing to share your project?