The main purpose of compact RDG room thermostats would be to control room temperature of single rooms and zones heated or cooled by fan coil units (2- or 4-pipe), dx type equipment, electrical heating, radiators, or VAV systems. The built-in sensor in the thermostat helps acquire the required current temperature and controls peripheral devices to reach and maintain the same. It is possible to connect the sensor and switch directly with the thermostat. Room thermostats featuring KNX bus communication (S-mode) are also available. The thermostats are mainly used in fan coil units, universal applications, compressors of dx type equipment and VAV heat and cooling systems.