I found it. I have a note written on it that it works on most Ademco and the private labeled Ademco stuff, but I don't know how long ago I wrote that note to myself:
1) Power down the system (unplug the transformer AND battery)
2) Plug in the transformer, and RUN to the keypad.
3) Within 30 seconds, press * and # on the keypad at the same time. You will see either "00" or "20" to let you know you're in programming mode.
4) You should be in programming - press #20 (this depends on the model of your system - could be #00, depending on what you saw in step 3)
5) The installer code will be read back to you (4 digits). Write it down! The code will read back in 2-digit format. IE: code 1234 will read 01 (beep)-02(beep)-03 (beep)-04 (beep).
6) If you wish to change your Installer access code simply press " * " + 00 OR " * " + 20 (What ever came up on your keypad when you first got into programming.) Then Enter Your New Code IE: *20 +1234. Your installer access code will now Be 1234.
7) Exit programming by pressing in *99