How to add the user code in AC100?

User number and user code can't be use repeatedly.
To add the user code:
Step 1: Enter programming mode (Press *, programming code, and # key).
Step 2: Press 501, enter the user number (3 digits), enter the user code (4 to 8 digits), and # key.
Repeat step 2 to adding multiple user codes.
Step 3: Press * key to exit programming code.