For modular door stations and letterbox systems. Control electronics for addressing the bell buttons. Nameplates illuminated by LED and labelable. Plug-in bus connectors for connection to the door station bus line. Plugs for connecting additional function modules. Installation dimensions: 95x95x33 mm (WxHxD). Dimensions of lettering field: 56x15 mm (WxH). Accessories: ==>Feedback board 18799.. for acoustic feedback. Color: white.