Reverse engineering a security keypad

When I previously did the reverse engineering work on my home security system, I just skipped trying to get the keypad working.

Since then someone posted some code to interface an arduino to the exact model of keypad I have in my house (a DSC PC1500RK).

This weekend I tried the code out and it worked perfectly!  Thank you caitsith2, who ever you are!

Now I just need to integrate this with my security node...