• Proximity – the most popular by far. With several card types, fobs for key rings the cards offer ID printing options and the read range varies from 30mm to over 3m depending on the technology used. • Card swipe – being used less and less but still used, the cards offer ID printing options. • Biometric – why carry a card when your fingerprint will do, or retina, or palm, or voice, or even face and body profile. • Coded access – via a keypad. Additionally, this might contain one common code for all users or have individual user codes.