oye

As near as I can tell you can swap the chip and add the door controllers to some pretty old panels. It does require the access chip upgrade, and then you just add the door controller to the keybus. The controller uses a keypad address on the system. The Gem access stuff is fairly new. Plenty of info is available for the ACM1D and 2D off the Napco website without entering the tech library. (have to have a password to enter tech library)