This device is a useful accessory for smoke detectors RK60, RK70 and RK80.
It gives out an acoustic signal when one of the detectors enter in preallarm state and therefore it issues a maintenance request.
On the front there’s a switch that allows the activation or deactivation of the piezoelectric buzzer. This module must be used with the EV570 module to have a double signal of preallarm of the linear detectors: acoustic and optical.
Every EV450 can control 5 linear detectors.