How do I enter Programming mode of a standalone controller if the default Master code fails?

How do I enter Programming mode of a standalone controller if the default Master code fails?

Check the color of left LED – is it green or red? If red, exit Secure mode by entering 3838# -> color of LED should be green now. If it still fails to enter Programming mode.
If left LED is green:
  1. Turn off the power of controller.
  2. Press and hold the REX button
  3. Turn on the power of controller
  4. Release the REX button
  5. Enter ## -> enter 1234 -> enter 3 -> enter 1234.
Starting from power up, the whole programming procedure must be finished within 15 seconds.

Now, the master code is reset to 1234