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Reputation: 93

Are NFC tags and NFC cards the same thing?

Are NFC tags and NFC cards the same thing? The Android documentation mentions both. "NFC tags" when reading simple tags, but then says "NFC card" in the HCE documentation. Can I assume these are the same?

Upvotes: 4

Views: 3220

Answers (1)

Michael Roland
Michael Roland

Reputation: 40851

In general the terms "NFC tag" and "NFC card" are somewhat interchangeable. They refer the same underlying chip technology packed into objects with different form factors. I.e. an NFC tag can have any form factor (e.g. a small sticker that you attach to any object) while an NFC card is typically something that has the shape of a credit card (e.g. ID1 format as defined in ISO/IEC 7810).

Usually, NFC tag/card refers to NFC Forum tags. These are simple memory tags (some may have additional processing capabilities though) that store (freely readable) data in NDEF format. NFC Forum tag technologies were originally built on top of exising RFID memory tag technologies that were all merged into NFC.

However, when it comes to host card emulation (HCE), the term "NFC card" (as used in the Android documentation) is somewhat misleading. In the case of HCE the term "card" (prepending "NFC" to it is the misleading part) actually refers to a contactless smartcard (typically ISO/IEC 14443-4). Consequently, a better description would be "NFC-compatible smartcard", since NFC devices typically support ISO/IEC 14443-4 in reader mode (i.e. they can access such smartcards) and often also in card emulation mode (i.e. they can be accessed by other ISO/IEC 14443-4 card readers).

Such a HCE-emulated card act as an NFC tag (more specifically an NFC Forum tag containing NDEF data) by implementing the NFC Forum Type 4 Tag Operation specification, a protocol that maps NDEF data structures to ISO/IEC 14443-4 smartcards. However, in many cases ISO/IEC 14443-4 smartcards speak different protocols, e.g. credit cards often speak EMV, electronic passports speak a protocol defined in ICAO 9303, etc.

Upvotes: 5

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