The Base Sounders Indoor FNM-420-A-BS-RD are used for signaling an alarm directly at the fire location. They can be employed either as base sounders or stand-alone sounders.
The base sounder can be operated with an FNS-420- R LSN Strobe or an automatic detector from the 425 series. The maximum number of devices on each loop depends on the cable diameter and the total current of the loop