How to change and reset default programming code?

To change the programming code:
Step 1: Enter programming mode (Press *, programming code, and # key).
Step 2: Press 0, enter new programming code (4 to 8 digits), # key, re-enter the new programming code, # key.
To reset the programming code:
Step 1: Disconnect the power supply.
Step 2: Switch the DPC jumper from OFF position to ON position.
Step 3: Reconnect the power supply (Yellow LED will blink and the buzzer will beep constantly).
Step 4: Place the DPC jumper back to OFF position.
Step 5: Press the # key.
The default programming code is 1234.