How does OpenTherm work?

Could you please elaborate on the functioning of OpenTherm? I'm curious to understand the technology behind it and how it enables communication between heating systems and their controllers. Specifically, how does it transmit data efficiently and securely, and what are the main benefits it offers to homeowners and building managers in terms of energy savings and improved system performance? Additionally, is OpenTherm compatible with a wide range of heating appliances, and how does it compare to other communication protocols in the industry?