Access Controllers provide the logic necessary to make the determination to either allow the cardholder access or not. To guard against card passback, access controllers can feature either timed or true anti-passback. Timed anti-passback requires a certain time to pass before the controller allows the same card access. True anti-passback requires the a card to enter and exit before the controller will allow the same card to open a gate. Access controllers can also be either online or offline capable.