An atmosphere controlling arrangement for provision in a building automation system, the arrangement comprising: a master control module having a housing and a master control unit controlling an atmosphere function in an area in or adjacent the building, a remote control module having a housing comprising a remote control unit for actuating the atmosphere function via the master control unit , wherein the housing (18; 24) of one of the control modules (14; 16) comprises at least one first slot adapted for receiving and mating with portable wireless communication modules, a first portable wireless communication module insertable in said first slot for connection to the control unit (28; 38) of the corresponding control module (14; 16) and equipped with a first wireless interface , wherein the arrangement comprises: a second portable wireless communication module equipped with a second wireless interface for the other of the control modules and configured to communicate wirelessly with the first wireless interface , such that the remote control module can actuate the atmosphere function when the first portable wireless communication module is inserted in the first slot, and the housing of the other of the control modules comprises a second slot adapted for receiving and mating with portable wireless communication modules, where the second portable wireless communication module is insertable in said second slot for connection to the control unit of said other of the control modules . a master control module having a housing and a master control unit controlling an atmosphere function in an area in or adjacent the building, a remote control module having a housing comprising a remote control unit for actuating the atmosphere function via the master control unit , wherein the housing (18; 24) of one of the control modules (14; 16) comprises at least one first slot adapted for receiving and mating with portable wireless communication modules, a first portable wireless communication module insertable in said first slot for connection to the control unit (28; 38) of the corresponding control module (14; 16) and equipped with a first wireless interface , wherein the arrangement comprises: a second portable wireless communication module equipped with a second wireless interface for the other of the control modules and configured to communicate wirelessly with the first wireless interface , such that the remote control module can actuate the atmosphere function when the first portable wireless communication module is inserted in the first slot, and the housing of the other of the control modules comprises a second slot adapted for receiving and mating with portable wireless communication modules, where the second portable wireless communication module is insertable in said second slot for connection to the control unit of said other of the control modules . a second portable wireless communication module equipped with a second wireless interface for the other of the control modules and configured to communicate wirelessly with the first wireless interface , such that the remote control module can actuate the atmosphere function when the first portable wireless communication module is inserted in the first slot, and the housing of the other of the control modules comprises a second slot adapted for receiving and mating with portable wireless communication modules, where the second portable wireless communication module is insertable in said second slot for connection to the control unit of said other of the control modules . <EOS>