U apply to voice and music playback u rugged surface of the metal case u installation and/or embedded inside u can install optional line/speaker monitoring board u EN 54-24 3018/01 certification LBC speakers with both solid and fashionable metal shell, to provide professional sound performance. It is especially suitable for indoor use in offices, schools, parking lots, shopping centers and other places. It is also suitable for dangerous areas where there may be destructive behaviors. These speakers are equipped with high efficiency speakers with a dual tone basin, which can provide a wide range of frequencies, so as to achieve excellent voice and music reproduction performance. Basic features these voice-activated alarm speakers are specially designed to be used in buildings that require the performance of the voice-activated evacuation broadcast system to meet official requirements. L30bc 18/01 is designed for voice alarm system and conforms to EN 54-24 standard. The speaker has built-in protection. In case of a fire, this protection ensures that the damage to the loudspeaker does not result in the failure of the circuit connected to it. In this way, the integrity of the system is maintained to ensure that the loudspeakers in other locations can still communicate to people in a timely manner. The loudspeaker is equipped with a ceramic junction box, a temperature fuse and a heat-resistant high-temperature conductor. An optional circuit/speaker monitor board can be installed inside the speaker box. All Bosch loudspeakers are certified to meet IEC 268-5 power amplifier (PHC) standards and can operate continuously for 100 hours at rated power. Bosch has also conducted simulated acoustic feedback exposure tests to ensure they can withstand twice the rated power in a short period of time. This ensures higher reliability in extreme conditions, improves customer satisfaction, extends service life, and significantly reduces the chance of failure or performance degradation. Security in accordance with EN 60065 standard emergency in 24, BS EN 54 ‑ ‑ eight 5839 and EN 60849 standard waterproof and dustproof meet EN60529 IP32 EU_CPR CPR certification Europe CE standard area Poland CNBOP installation/configuration size (unit: mm (inches)) 2 x ø 20 size (unit: mm (inches)) this speaker can be mounted to the wall surface, can also be embedded into the brick wall or concrete wall. The speaker box has optional mounting holes in the bottom box, so it can even be mounted on the U40 and MK mounting boxes. There are two holes in the top of the bottom box for installing two cable seal plugs to form a loop connection. For convenience, the safety cable of the bottom box allows the installer to suspend the front mask temporarily during installation. Surface mounting (left) and embedded mounting (right) speakers have a three-way junction box with a screw connector suitable for loop wiring (including grounding). The matching transformer has four jumper lines, so the user can easily select rated full power, 1/2 power, 1/4 power or 1/8 power (amplitude: 3db). 4 C 6W 3W 1.5w 0.75w-70v c-6w 3W 1.5w 0.75w 100V circuit diagram frequency response directivity diagram (measured by pink noise)