GR-52 is an indicator LED which is cooperated with the "HOTEL ACCESS" devices GR-45, GR-46, GR-47 or with any control unit with 230VAC output (e.g.infrared movement detector GR-55). It is installed away from the device and lights when a device is activated. It is used in buildings that are separated in small places (hotel΄s rooms, hospitals, offices). Usually it is installed above of the room door which is visible from a long distance. Using the GR-52 we can realize in which room there is occupant without to open the door of the room.