A security system is provided to integrate a local existing security system with other security and automation devices which may not be compatible with the existing security system. The security system can connect and integrate an existing security system, and provide a centralized point of controlling all existing and new security and automation devices in a premise, thereby allowing flexibility in modifying and expanding a security system in the premise without need of replacing the security system that has been already installed throughout the premise. The security system can at least partially self-program to communicate with an existing security system when the security system is connected to the existing security system.