Terminology » NFC Standards: Type 2 (T2T) vs Type 4 (T4T) Tags

NFC Standards: Type 2 (T2T) vs Type 4 (T4T) Tags

nfc standard nfc tag type 2 tag type 4 tag t2t t4t

Introduction : The NFC Forum defines five specific “Tag Types” to ensure interoperability between NFC readers (like smartphones) and passive transponders (tags). Among these, Type 2 and Type 4 are the most widely deployed, but they serve vastly different purposes. Let us understand these tag types and explore differences between them.

NFC Type 2 Tag (T2T)

The Type 2 Tag platform is designed for simplicity and low cost. It is lightweight, efficient and perfect for disposable applications.

  • Protocol: It is based on ISO/IEC 14443-3 Type A. Crucially, it does not support the higher level ISO DEP protocol. It communicates using a simple command set directly over the air interface.
  • Memory Structure: T2T uses a flat memory model. The memory is divided into Pages (blocks) of 4 bytes each.
  • Static Memory: For tags < 64 bytes.
  • Dynamic Memory: For larger tags, using a segment management strategy.
  • NDEF Handling: To store an NDEF message (like a URL), the tag uses a TLV (Type Length Value) wrapper inside the data blocks. The reader simply looks for a specific “Message TLV” (Tag 0x03) to find the content.

Example Chips :

  • NXP NTAG Series
  • Mifare Ultralight family

NFC Type 4 Tag (T4T)

The Type 4 Tag is essentially a contactless smart card. It is designed for applications where security, large data capacity and standardized file access are required.

  • Protocol: It is based on ISO/IEC 14443-4, supporting the ISO-DEP (Data Exchange Protocol). This layer provides robust error correction and flow control. Physically, it can use either Type A or Type B modulation.
  • Memory Structure: Unlike the flat blocks of T2T, T4T uses a File System structure derived from ISO/IEC 7816-4.
    • NDEF Application: Data is stored inside a specific “NFC Application” selected by its ID (AID).
    • Files: Inside this application, there are distinct files, such as the Capability Container (CC) and the NDEF File.
  • NDEF Handling: The reader does not just “scan memory.” It must “Select” the application, “Select” the file, and then issuing “Read Binary” commands.

Example Chips :

  • NXP MIFARE DESFire series
  • STMicroelectronics ST25TA series

Comparison: T2T vs. T4T

FeatureType 2 Tag (T2T)Type 4 Tag (T4T)
Underlying StandardISO/IEC 14443-3 (Type A)ISO/IEC 14443-4 (Type A or B)
CommunicationProprietary / Simple CommandsISO-DEP (APDU based)
Memory AccessFlat Addressing (Blocks/Pages)File System (EF, AID)
Data RateTypically 106 kbit/sUp to 424 kbit/s (or higher)
Max Memory (Typical)48 Bytes to 2 KB2 KB to 32 KB (up to megabytes)
SecurityBasic (Lock bits, simple password)Advanced (AES/DES encryption)
Primary Use CaseSmart Posters, URL sharing, TicketingPayments, Passports, High security Access
Example ChipsNTAG 213, MIFARE UltralightMIFARE DESFire EV3, ST25TA

Conclusion

If your project requires a cheap tag to trigger a URL, launch Wi-Fi pairing or perform basic inventory tracking, Type 2 (T2T) is the correct choice. It is cost efficient and universally supported.

However, if you are building a closed loop payment system, a secure ID badge or need to store large amounts of data reliably, you must use Type 4 (T4T). The added cost provides the necessary cryptographic security and robust communication protocol that T2T lacks.

References for further study

  1. NFC Forum, “NFC Type 2 Tag Specification” and “NFC Type 4 Tag Specification,” nfc-forum.org
  2. ISO/IEC, “ISO/IEC 14443-3 and 14443-4 Identification cards — Contactless integrated circuit cards,” iso.org.