8KHZ:Press “OFF” button 1 time within 3 seconds and press “ON” button 5 times, Activated successfully once led light flashes 2 times quickly.
250HZ:Press “ON” button 1 time within 3 seconds and press “OFF” button 5 times, Activated successfully once led light flashes 2 times slowly.
Warm tips: user can change low frequency(250HZ) to avoid the beep noise from mains, checking video