Technical Library

NFC Tags

NFC tags are simple devices containing an antenna and a limited amount of memory. Because they are passive devices without power, NFC tags are used to communicate with active NFC readers and writer. When an active NFC device touches the tag, the tag takes a small amount of power from it and activates its electronics to transfer data to the NFC device.

Usually, a small amount of data is stored on the NFC tag's memory to serve as a pointer to other information; for example URLs to resources. The tags can be embedded in various mediums for accessing; for example a poster can contain a tag.

The initial NFC tag specification was released by the NFC Forum in 2006. The NFC Forum defines four types of tags that provide different communication speeds and capabilities in terms of configurability, memory, security, data retention, and write endurance. Refer to the Table 1 for the tags standards, features, memory limitation, and speed. NFC Forum Tag Type Technical Specifications can be downloaded after a license agreement is signed.

Tag Type	Standard	Features	Memory	Speed
1	ISO-14443A	Read, re-write or read-only; No data collision protrection	96 bytes; expandable to 2KB	106 Kbits/second
2	ISO-14443A	Read, re-write or read-only; No data collision protrection	48 bytes; expandable to 2KB	106 Kbits/second
3	JIS X 6319-4	Read, re-write or read-only; No data collision protrection	Variable memory, up to 1 MB per service	212 or 424 Kbits/second
4	Compatible with ISO14443 (A&B)	Read, re-write or read-only; No data collision protrection	Variable memory, up to 32 KB per service	106, 212 or 424 Kbits/second

Table 1: NFC Tags

An NFC reader is an active device that generates radio signals to communicate with NFC tags based on the ISO 15693 standard, provided that the tags employ the NFC Data Exchange Format (NDEF).

To download the complete NDEF specifications, go to the NFC Forum Specification Download site.