Building management systems are used to control different building systems such as the heating, solar screening equipment, and the lighting. They are more complex than systems that solely control the lighting and thus are more involved in terms of planning, installation and operation. An established protocol ensures communication between the systems over a flexible network. The control systems form the basis for building automation, to simplify and automate the different functions in a building. The building automation is divided into three levels: the management level for user-friendly visualisation, the automation level for data exchange, and the local level with sensors and actuators. There are no integrated receiving devices in the luminaires (interfaces) for decoding control signals; lighting control is achieved by wiring individual circuits.