The optical VdS wireless smoke alarm device reacts to visible fire smoke within its detection range. If an alarm detects smoke particles in the air, all alarms in the building are triggered. The wireless smoke alarm device is installed on the ceiling. Minimum distances to the wall (15 cm), corners (50 cm), etc., must be observed (for details see the user guide). We recommend a separate detector for each hallway, staircase, living room, and bedroom. If a detector detects smoke, the piezo sounder emits an alarm which is 85 dB loud – from all detectors at the same time. The detector that first detected the smoke can be identified by an alarm tone that is different from the others.<CRLF><CRLF>Up to 32 smoke detectors can be networked wirelessly – each with a range of up to 30 m (additional wireless modules are not required). The cascading of the detectors guarantees a high level of safety; an alarm is passed across the entire chain from the first to the last detector. The effective range does however depend on the structural characteristics (a wireless test is recommended before installation). The batteries recommended have a lifespan of up to 2 years. The detector reports a weak battery by emitting regular beeps. We recommend that the detector be tested once per month. The detector is VdS-certified thanks to the high level of safety and reliability it provides.