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

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.