Vandalcom module Art. 3183SV allows for the visual/acoustic signalling of the system’s operating status by reproducing voice messages and the switching on of 4 LED s: LED 1 red: call awaiting a response, LED 2 yellow: conversation under way, LED 3 green: active locking, and LED 4 blue: engaged line. DD A compliant. Dimensions: 106 x 106 x 56 mm