The Homematic IP outdoor alarm siren provides reliable acoustic and visual alarm notifications within the Homematic IP smart home system. The wireless alarm siren can effectively signal break-ins or other events both audibly and visually. For this purpose, the outdoor siren is equipped with two powerful piezo speakers and prominent signal LEDs, all housed in a weatherproof enclosure with an IP44 protection rating. The alarm can be triggered, for example, by a Homematic IP motion detector or a Homematic IP window and door contact. Thanks to the direct connection between the devices, the alarm activation works reliably even in the absence of an internet connection or if the Homematic IP access point or the central CCU2/CCU3 fails. Additionally, the siren features a tamper contact that triggers the alarm in case of unauthorized disassembly attempts. The sustainable power supply via a solar cell combined with a backup battery means that no separate power supply is required for installation. This allows the alarm siren to be mounted in hard-to-reach locations. The battery ensures reliable operation even at night or on cloudy days. Furthermore, the siren can also be recharged via the micro-USB port if needed.