I’m using a 202 to power on piezo tweeters at 35khz. Since this is beyond human hearing I never know if the 202 is functioning. Question: does the buzzer in the 402 sound off the entire time the unit is active?
The buzzer on 402u will turn on when either relay is active.
For 202u receiver, you can solder a +5v buzzer to our onboard port (beside dip switches, with +5v 0 printing), it then will turn on when SIG is on.