monitor MAC address

There is a small hole at the bottom of the monitor, use a pen or paper clip to hold the button inside the hole. When you hear 4 beeps, release the button. Then go to your phone’s WiFi list, you will see a network name with this format GDB_xx:xx:xx:xx:xx:xx. The part after ‘GDB_’ is the MAC address.  Once you get the MAC address, you can disconnect the batteries and reconnect the batteries.  The monitor will go back to the regular working state.