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.
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