The NFC Operating Modes

By Robert R. Sabella

Part of NFC For Dummies Cheat Sheet

The operating mode determines the specific kind of task that NFC is performing at any given time. The devices interacting at the time allow for certain operating modes. Here’s a quick overview of the NFC operating modes:

  • Card emulation mode: This mode places the NFC device in passive communication mode. The device acts precisely the same as a smart card. Your NFC-enabled device can emulate more than one smart card, and the smart card support can include more than one form of identification.
  • Reader/writer mode: When working in reader/writer mode, most NFC devices act as readers. The NFC device works in active mode to read the content of a tag. When it detects two or more tags, it relies on an anticollision algorithm to select just one tag. The NFC device must also detect the tag type (ISO/IEC 14443 A/B or FeliCa) and interact with it appropriately.

    An NFC device can also write data to the tag. To write data to a tag, you must have a tag writer application, such as TagWriter, installed on your device.

  • Peer-to-peer mode: Two powered devices can engage in peer-to-peer mode, which is NFC specific. This mode lets the two devices converse as though networked together. During the initial communication, the two devices determine the communication parameters, such as data block size. The maximum data block size is 256 bytes.

    In many cases, peer-to-peer mode is used for pairing of the devices to use some other means of transferring the actual data, such as Wi-Fi or Bluetooth. The use of NFC for pairing greatly reduces the work required to pair two devices, such as a smartphone and Bluetooth wireless speakers.