... signals input for push button,15000cards Technical Parameters1) Storage: use FLASH to store, 10000 single or double cards user, maximum number of ... 4 group output of alarm, you can choose NC/NO to control door close/open.6) Photocoupler , and lightningproof interface ... power.2) Many modes for opening: button for opening, software to control opening, card, double cards, card + password(6 bit), ...