the keycode are assigned to your system id. if you pull the software cartridge, your system id will change and your keycodes are gone. good luck trying to get them from nortel. I have a theory that their a set amount of sys id in every mics cabinet and if you had a list of sys id that have keycodes recorded, you could cycle through pulling the cartridge out and your sys id would come back around to put your matching keycode in again, if you have them of course. have never made a list of system id and pri keycodes to check this out but I know the system id changes if you remove the software cartridge. sure would like to start a list of sys id and pri keycodes from people. I have about 7 right now.