What are Access Cards?
Access control systems are a norm in commercial buildings these days. For instance, we see them used to access offices, turnstiles, and other entry points in buildings. They are handy as there is no need to carry too many keys around. A single card can be programmed to enter various locations. All types of access cards have a similar function which is to unlock doors. There are many types and brands of access cards these days. The concept of cards being used as credentials first came from the Wiegand Card.
Wiegand Access Cards
John Wiegand developed the first access card in the 1970s. A Wiegand key card uses two parallel lines of short Wiegand wires to store binary data in magnetic polarity. The Wiegand wires register as ones, and the blank spots are zeroes as the card goes through the reader. A controller receives This unique Wiegand number and authenticates it. These types of cards are rarely in operation these days. However, the Wiegand interface is still the de facto standard for wiring between controllers and readers.
Barcode/QR Code Cards
Barcodes have mostly evolved into QR Codes these days. However, we still see them used in visitor management systems or National Identification systems. How it works is simple. The reader (usually a laser) reads the presented barcode or QR code on the card. The laser sends the code data to a database. If the sent code and the identity in the database matches, then access is granted.
Magnetic Stripe Cards
Have you ever looked at the back of your credit card? Did you notice a thick black line running its entire length? The black stripe is tiny polarised magnets in multiple tracks. Swiping the black stripe or bar across the magnetic read head inside the lock causes a varying voltage. The reader head measures the changing voltage and converts it to a binary credential. Magnetic swipe cards use the same technology as your credit cards. We typically come across such cards in hotels to access hotel door locks.
Proximity (RFID) Access Cards
Proximity/Prox or RFID Cards are contactless credentials. They use Radio Frequency Identification to transmit data stored on a microchip. Prox cards use a low frequency of 125khz to communicate with the reader. Readers continuously send out a short-range radio signal. When the chip is in range of the radio signal is powers up via passive induction. Powered up chip sends the data to the waiting reader. The reader receives the data and sends it to the controller. Controller unlocks the door if the identity matches.
Smart Cards
Smart Cards typically refer to High-Frequency RFID cards that use Near-Field Communication to transmit data. NFC technologies operate at 13.56 MHz. Most smart cards use passive induction for power. However, some smart cards have additional tiny lithium batteries within them for active powering. Smart cards have larger storage capacity than 125kHz cards which also allows them to encrypt their data. Contactless payment systems typically use Smart Cards as well.
As shown above, there is a myriad of access card types available in the market today. Each class has various pros and cons. They can be used in a variety of functions and not just for access control alone. Selecting the best kind of access card for your organisation depends very much on its purpose. Contact us, and we can advise you in choosing the right type of access card.
