Buzzer light alert. The buzzer sound changes depending on the registration number (up to 8 units can be registered). [Registration method for receiver] Press the selection button to enter the registration state. Select the number you want to register and stop the operation of the select button (call light flashing); Activate the registration (step) when this unit is received.After about 2 seconds later, turn off to complete registration: Press the selection button to choose the desired number, the call lamp will flash. When flashing, press the registration delete button for more than 2 seconds. When the delete is complete, the call light will flash, short flash, and turn off.