ISO 14443

ISO 14443 -- Proximity Contactless Smart Cards

ISO/IEC 14443 is the international standard for proximity contactless smart cards operating at 13.56 MHz with a communication range of up to 10 cm. It underpins contactless payment (EMV tap-to-pay), transit ticketing, and access control systems worldwide. The standard is divided into four parts covering physical characteristics, radio frequency interface, initialization and anti-collision, and the transmission protocol.

Type A and Type B

ISO 14443ISO 14443StandardStandard for contactless smart cards.Click to view → defines two signaling variants. Type A, used by NXP's MIFARE family and most EMV contactless cards, employs 100% ASK modulation with Miller encoding for the reader-to-card link and load modulation with Manchester coding for the card-to-reader link. Type B uses 10% ASK modulation with NRZ-L encoding, offering better noise immunity and is commonly found in government identity documents and ePassports. Both types operate at 13.56 MHz and support data rates from 106 kbit/s up to 848 kbit/s.

Anti-Collision and Card Selection

Part 3 of the standard defines how a reader detects and selects individual cards when multiple cards are within the RF field. Type A uses a bit-level anti-collision algorithm based on the card's unique identifier (UID), while Type B employs a slotted ALOHA time-division scheme. After anti-collision resolves which card to communicate with, the reader sends a RATS (Request for Answer to Select) command, and the card responds with its ATS (Answer to Select) -- analogous to the ATR in the contact interface.

Relationship to Other Standards

ISO 14443 works alongside ISO 7816-4 for the APDUAPDUProtocolCommunication unit between card and reader.Click to view → layer. Dual-interface modules combine both contact (7816) and contactless (14443) interfaces on a single secure element. The EMVCo contactless specifications (Books C and D) build on 14443 with additional payment-specific requirements. FIDO2 security keys with NFC capability also rely on ISO 14443 for the physical transport layer, wrapping CTAP2 commands inside 7816-4 APDUs transmitted over the contactless interface.