Distributed Control System
Distributed control systems use wiring already in the home, such as standard power line wiring, telephone wire (4 pair), video wire, radio frequency (RF) signals and infrared (IR) signals.
Microchip controls installed in appliances or outlets enable individual appliances to communicate with each other over the existing electrical wiring without a central controller, although keyboard entry is possible using telephones or personal computers.
The system’s status can be monitored on the home TV set. Compatible appliances are necessary. To achieve a common standard, the Electronic Industries Association has developed a standard communications protocol, (protocol = a set of rules governing the format of messages that are exchanged between computers), which will allow appliances and modems from different manufacturers to communicate with each other.
Individual semiconductor manufacturers have developed microchips that could be installed in appliances.
Reference: National Kitchen & Bath Association (NKBA)