The programming location for the keypad on address 23 is location 196.

Press * (the asterisk button on the lower left of the keypad) then press 196, pause, then press 1 0.
If successful you'll hear three chimes from the keypad.

That's all the Vista 20P programming necessary to enable your new keypad.

Press * 99 to exit installer programming.

The Vista 20P will take a couple of minutes to reset and become active with your new keypad enabled.

Click "Next" to continue...