1. Core Radio Frequency (RF) Protocols (The "Physical" Layer)

These define the physical modulation, data rate, and anti-collision methods.

• ISO/IEC 18092 (NFCIP-1): The base standard for NFC interface and protocol.

• ISO/IEC 21481 (NFCIP-2): Defines how devices switch between different RF technologies.

• NFC-A (ISO/IEC 14443A): Common in MIFARE Classic and Ultralight tags.

• NFC-B (ISO/IEC 14443B): Used for higher security applications (e.g., passports, some payment cards).

• NFC-F (JIS X6319-4 / FeliCa): Sony's standard, popular in Asia (e.g., Japan's Suica, Hong Kong's Octopus).

• NFC-V (ISO/IEC 15693): Designed for longer range (up to 1m) inventory tracking (Vicinity cards).

2. Data Exchange Protocols (The "Transport" Layer)

These manage how two active NFC devices (e.g., two phones) talk to each other.

• ISO-DEP (ISO/IEC 14443-4): Enables the exchange of APDUs (Application Protocol Data Units) used by smart cards (e.g., MIFARE DESFire, payment cards).

• LLCP (Logical Link Control Protocol): Establishes a two-way connection between devices (similar to TCP).

• SNEP (Simple NDEF Exchange Protocol): Allows devices to send and receive NDEF messages over an LLCP link (used for Android Beam).

• RTD (Record Type Definition): Defines standard record types (Text, URI, Smart Poster, Handover, etc.).

3. Host Interface Protocols (The "Internal" Layer)

These are internal protocols between the phone's main CPU and the NFC chip.

• NCI (NFC Controller Interface): The standardized communication protocol between the device's main processor and the NFC controller.

• HCI (Host Controller Interface): Used for managing multiple secure elements (e.g., SIM card, embedded SE).

• NFC-WI (Wired Interface): Allows a separate Secure Element (like a SIM card) to share the antenna connection.

Summary Table by Use Case