- Pilot tone detection on 100 V loudspeaker lines
- Voltage free switch 200 V 1 A and LED indications of pilot tone
- Daisy chainable for monitoring multiple zones on a single input contact
- Fits on built-in mounts on selected Bosch loudspeakers
- EN 54‑16 certified
A Plena end-of-line board is a PCB designed to detect the 20 kHz pilot tone generated by a supervised public address or voice alarm system. It activates a voltage free switch in the presence of a 20 kHz signal (pilot tone) above 5 V, as well as an LED for easy visual confirmation of operation.