Step 1. Press and hold the "M" key for 3 secs to enter test mode.
Step 2. Put the test lamp tool vertically on the 2 contact points, making sure the metal wire of the test lamp has direct contact with the top of the 2 points.
Step 3. Shout" WO WO" aim to the Microphone, the device responds to the beep and vibration function. The test lamp will be lit.
Step 4. After the test is completed, press and hold the "M" key for 3 seconds to exit the test mode.
