I have Ring Pro 2, purchased specifically to use existing doorbell wiring and indoor mechanical chime. Instructions had me install the Ring Pro Power Kit onto the indoor chime. While the Ring video and outdoor chime worked, the indoor chime did not. Customer service was very helpful in troubleshooting. We learned with Ring Pro 2, on some chimes, the Pro Power Kit is not needed. Once I removed the Pro Power Kit the indoor mechanical chime worked with the Ring Pro 2 doorbell. Kudos to the Ring Customer Service person, Jackie, who called me back when our phone call was disconnected.