Contactless Cards
These are smart cards that employ a radio frequency (RFID) between card and reader without physical insertion of the card. Instead, the card is passed along the exterior of the reader and read. Types include proximity cards which are implemented as a read-only technology for building access. These cards function with a very limited memory and communicate at 125 MHz. Another type of limited card is the Gen 2 UHF Card that operates at 860 MHz to 960 MHz.
True read and write contactless cards were first used in transportation applications for quick decrementing and reloading of fare values where their lower security was not an issue. They communicate at 13.56 MHz and conform to the ISO 14443 standard. These cards are often protected memory types. They are also gaining popularity in retail stored value since they can speed up transactions without lowering transaction processing revenues (i.e. Visa and MasterCard), unlike traditional smart cards.
Variations of the ISO14443 specification include A, B, and C, which specify chips from either specific or various manufacturers. A=NXP-(Philips) B=Everybody else and C=Sony only chips. Contactless card drawbacks include the limits of cryptographic functions and user memory, versus microprocessor cards and the limited distance between card and reader required for operation.
