Your ADT security system uses four-digit security codes to arm and disarm the system. Most ADT alarms store up to 16 different user codes plus the master code. It is advisable to reset the master code on the alarm periodically. The master code is the only code that can add or delete other users to your alarm. Resetting the master code once a year adds extra security by denying users an opportunity to discover your code and change the system without your knowledge. The existing master code is necessary to reset the ADT security code. The steps to resetting the master code are similar to all models of ADT alarm systems.
Enter the current four-digit master code into the alarm keypad. Press the "Code" button key. The "Code" button is indicated under one of the number keys on the keypad, usually the number 8.
Press the "0" and the "2" keys on the keypad. This is the indicator that the master code is being reset. Enter a new four-digit master code into the keypad.
Wait three seconds, then enter the new master code and press the "Status" key. The system checks the status of all sensors and zones using your reset master code.
Consult your user manual for specifics on your model.