Control module for room automation that can be operated with a HAC7000/32 control panel or optionally in standalone mode. The room controller has three RS485 interfaces (2-wire) for connecting to the control panel (COM1), for connecting the room automation control panels (COM2, room bus), and, depending on the configuration, for connecting a reader (COM3, reader bus). The terminal devices to be controlled are connected to the inputs or outputs. To add additional room or climate functions, up to four expansion modules can be connected to the controller via the system bus connection.