Every MIFARE-based hotel keycard in the world operates according to ISO/IEC 14443, the international standard for contactless smart cards. Published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), this standard defines how a contactless card communicates with a reader at 13.56 MHz — the same frequency used by NFC in smartphones.
The Four Parts of ISO 14443
The standard comprises four parts:
- Part 1 — Physical Characteristics: Defines the card's physical dimensions (CR-80, 85.6mm x 53.98mm x 0.76mm), UV exposure resistance, and mechanical bending tolerance.
- Part 2 — Radio Frequency Power and Signal Interface: Specifies the 13.56 MHz operating frequency, field strength requirements, and the two communication interfaces: Type A (used by MIFARE) and Type B.
- Part 3 — Initialization and Anti-collision: Defines how a reader identifies and selects a specific card when multiple cards are within range — critical for preventing unintended access in hotels with dense reader installations.
- Part 4 — Transmission Protocol: Specifies the half-duplex data communication protocol used by advanced cards like MIFARE DESFire (T=CL protocol).
Type A vs Type B
ISO 14443 defines two radio interface types. Type A is used by the NXP MIFARE family (Classic, DESFire, Ultralight) and is the dominant standard in hotel access control worldwide. Type B is used primarily in government ID and transportation applications. For hotel keycard procurement, Type A (ISO 14443-A) compatibility is the standard requirement.
Why the Standard Matters
ISO 14443 compliance ensures interoperability: a compliant keycard from any manufacturer will communicate with any compliant reader from any lock manufacturer. This interoperability is what allows hotels to source keycards independently of their lock vendor, creating competitive procurement options and preventing vendor lock-in.
