NFC-A, NFC-B, and NFC-F: Protocol Differences Explained

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This article breaks down the distinctions between NFC-A, NFC-B, and NFC-F, three signaling protocols used in Near Field Communication (NFC). NFC technology has become incredibly widespread for short-range communication, particularly in applications where low data rates are sufficient.

As you know, NFC enables devices to communicate over short distances. A crucial aspect of this communication is the signaling protocol, which dictates how devices exchange information. NFC employs three primary signaling modes: NFC-A, NFC-B, and NFC-F. Before communication begins, both the initiator and the target need to agree on which technology to use as the signaling protocol. Here’s a detailed look at each:

NFC-A

  • Based On: ISO/IEC 14443A (similar to RFID Type A)
  • Encoding: Miller encoding (delay encoding)
  • Modulation: AM modulation
  • Data Rate: Approximately 106 Kbps
  • Details: In NFC-A, binary data is transmitted using Miller encoding. To differentiate between binary 1 and 0, the binary signal must transition from 0% to 100%. This is a fundamental aspect of how data is represented in this signaling type.

NFC-B

  • Based On: ISO/IEC 14443B (similar to RFID Type B)
  • Encoding: Manchester encoding
  • Modulation: AM modulation (10%)
  • Details: NFC-B utilizes Manchester encoding. Instead of a full 100% AM modulation, a smaller 10% modulation is used. This modulation level is used to distinguish between binary 1 and 0. A 10% change from 90% (low) indicates a binary 0, while 100% (high) represents a binary 1. Manchester coding ensures a zero crossing within each bit period, with a low-to-high transition representing a binary 0 and a high-to-low transition representing a binary 1. The zero crossing is typically positioned in the middle of the bit period.

NFC-F

  • Based On: FeliCa JIS X6319-4
  • Also Known As: FeliCa
  • Details: NFC-F is a faster form of RFID communication and is widely used in Japan. It supports various applications, including credit/debit card payments, subway ticketing, and personal identification for access control in offices and residential buildings.

NFC Interview Questions and Answers

Prepare for NFC job interviews with this guide to common questions and answers covering NFC technology, applications, and security.

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