NFC Forum Tags
NFC Forum Tags are contact-less memory cards hosting a so called NDEF message (NDEF is standing for NFC Data Exchange Format) defined by an NFC Forum Specification. NFC Forum has currently defined five different NFC Forum Tag types to allow the usage of many different existing memory card implementations as NFC Forum Tags. These different NFC Forum Tag types differ by the underlying communication protocol and data structure to store NDEF messages but the resulting overall behavior of NFC Forum Tags is identical.
An NFC Forum Device reading the NDEF message from an NFC Forum Tag will initiate a specific action according to the information stored in this NDEF message. As lots of information can be stored in an NFC Forum Tag, there are many different actions triggered when read by the NFC Forum Device. The following table shows some of the common used data types and the typical corresponding actions initiated by the NFC Forum Device:
Depending of the actual context, the NFC Forum Device may also trigger alternative actions. For example, if the NFC Forum Device identifies that it is already connected with the Bluetooth Device when reading an NFC Forum Tag with Bluetooth pairing information, then the NFC Forum Device may disconnect the connection with this Bluetooth device.
For security sensitive actions, the NFC Forum has also defined a mechanism to add a signature to the NDEF Message allowing the user to verify if the NDEF message was generated by a trustworthy source.
Apps installed on NFC Forum Devices can extend or modify the behavior when the NFC Forum Device reads NFC Forum Tags. This allows for many additional data types which can be stored on NFC Forum Tags to trigger different actions on the NFC Forum Device. To support such applications, the NFC Forum specification also provides the definition of proprietary data formats which are identified by the internet domain namespace from the application provider.