Low-frequency, high-frequency, and ultra-high-frequency RFID technologies each have their own advantages and application scenarios, governed by distinct RFID communication protocols. Among them, access cards, bus cards, ID cards, and library tags—closely tied to daily life—primarily leverage high-frequency RFID, which relies on standardized RFID communication protocols like ISO 14443 and ISO 15693.
1.High-frequency RFID protocol
The RFID tag protocol is jointly established by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). It serves as the foundation for communication between RFID devices and is also the basis for tag chip design. From a standards perspective, the 13.56 MHz high-frequency band primarily encompasses two protocols: ISO 14443 and ISO 15693. The key distinction between the two is that ISO 14443 employs near-field coupling, while ISO 15693 uses far-field coupling. ISO 14443 incorporates encryption functionality, whereas ISO 15693 offers superior penetration capabilities and stronger resistance to interference. Of course, some 15693 chips now also incorporate encryption features to expand their application scope.
The terms “near-field” and “far-field” in near-field and far-field coupling are relative.
Contactless card standards include ISO/IEC 10536 (Close Coupled Cards), ISO/IEC 14443 (Proximity Cards), and ISO/IEC 15693 (Vicinity Cards). These standards are applicable to scenarios where the card is very close, relatively close, or at a certain distance from the coupling device, respectively.
2.ISO 14443 Protocol
ISO 14443 is a protocol for short-range contactless communication, primarily used in high-frequency (13.56 MHz) RFID systems. It is divided into two types: ISO 14443-A and ISO 14443-B. ISO 14443 is divided into four parts, each corresponding to a different layer.
• ISO 14443-1: Defines physical characteristics, which can be understood as the physical layer
• ISO 14443-2: RF power and signal interface
• ISO 14443-3: Initialization and anti-collision mechanism
• ISO 14443-4: Transmission protocol
ISO 14443-A and ISO 14443-B are both divided into these four parts, with most being shared, though some sections describe A and others describe B. For software developers, the primary focus is on the ISO 14443-3 and ISO 14443-4 protocols. Initialization and anti-collision-related content is covered in ISO 14443-3.
The main differences between ISO 14443-A and ISO 14443-B lie in modulation methods, encoding methods, and anti-collision mechanisms. A detailed comparison is shown below:
Anti Counterfeiting NFC Tags – ISO/IEC14443-A Certified for Secure Product Authentication
| Feature | ISO/IEC 14443-A | ISO/IEC 14443-B |
|---|---|---|
| Modulation | 100% ASK | 10% ASK |
| Encoding | Miller coding (Reader to Tag) Manchester coding (Tag to Reader) | NRZ-L coding |
| Anti-Collision | Bit-wise anti-collision protocol | Slot-based anti-collision protocol |
| Data Rate | Default: 106 kbit/s Higher rates supported: 212 kbit/s, 424 kbit/s, 848 kbit/s | Default: 106 kbit/s Higher rates supported: 212 kbit/s, 424 kbit/s, 848 kbit/s |
| Communication Range | 0 to 10 cm (Typical: 4 cm) | 0 to 10 cm (Typical: 4 cm) |
| Security | Supports encryption and authentication | Enhanced security and encryption mechanisms |
| Main Applications | Payment systems (e.g., MIFARE cards), Access control, Public transport, Attendance systems | High-security applications (e.g., e-ID cards, Electronic driving licenses) |
3.ISO 15693 Protocol
ISO 15693 is a protocol for long-range contactless communication, divided into three parts:
• ISO 15693-1: Defines physical characteristics, which can be understood as the physical layer
• ISO 15693-2: Radio frequency power supply, signal interface, and initialization
• ISO 15693-3: Anti-collision mechanism and transmission protocol
For software developers, the primary focus is on ISO 15693-3. This part provides detailed specifications on the storage structure of the VICC, the anti-collision process, the request and response data formats for communication between the VCD and VICC, and the main commands. The key technical features are as follows:
• Communication range: 0 to 1.5 meters (typical value: 1 meter)
• Primary applications: asset management, library management, supply chain management, and the medical field
• Modulation method:
• Reader to tag: Uses ASK (Amplitude Shift Keying) modulation with a modulation depth of 10% or 100%.
• Tag to reader: Uses Load Modulation
• Encoding method:
• Reader to tag: Uses 1/4 encoding, where each bit is encoded as 4 carrier cycles.
• Tag to reader: Uses Manchester encoding.
• Communication rate: High-speed 26.48 kbit/s, low-speed 6.62 kbit/s.
• Anti-collision mechanism: Uses Slotted Aloha protocol, resolving conflicts through slot allocation, and supports multi-tag reading.
• Security: Supports EAS (Electronic Article Surveillance) functionality for theft alarms. This depends on whether the tag supports this feature. Some 15693 chips also include additional encryption features, such as the Huada Semiconductor 15693, which incorporates the national cryptographic standard SM7.
• Storage capacity: Typical storage capacity ranges from 1 KB to 4 KB, depending on the tag model.
• Read/write mode supporting ISO/IEC 14443 type A and MIFARE Classic communication mode
• Read/write mode supporting ISO/IEC 14443B
• Read/write mode supporting JIS X 6319-4 (comparable with FeliCa)1
• Passive initiator mode according to ISO/IEC 18092
• Read/write mode supporting ISO/IEC 15693
• Read/write mode supporting ICODE EPC UID/ EPC OTP
• Read/write mode supporting ISO/IEC 18000-3 mode 3/ EPC Class-1 HF
RFID Sticker
4.High-frequency RFID read/write module
When it comes to 13.56 MHz high-frequency chips and manufacturers, NXP is a name that cannot be ignored. A search on search engines and e-commerce platforms reveals that most of the products that appear frequently are NXP products. Examples include MFRC522, CLRC663, PN532, and PN5180.
4.1MFRC522
The RC522 is a chip designed for contactless communication at 13.56 MHz, supporting ISO/IEC 14443 A/MIFARE and NTAG standards. It supports three serial communication interfaces: SPI, UART, and IIC. [2] Under optimal antenna and tuning conditions, the typical operating distance in read/write mode can reach 50 mm. This read/write module is cost-effective, with prices typically around 5 yuan on e-commerce platforms.
4.2CLRC663
The CLRC663 is a full-protocol read/write module supporting NFC. It supports three serial communication interfaces: SPI, UART, and I²C. It is cost-effective, with prices generally under 50 yuan. It supports the following operating modes: [3]
• Read/write mode supporting ISO/IEC 14443 Type A and MIFARE Classic communication mode
• Read/write mode supporting ISO/IEC 14443B
• Read/write mode supporting JIS X 6319-4 (comparable with FeliCa)1
• Passive initiator mode according to ISO/IEC 18092
• Read/write mode supporting ISO/IEC 15693
• Read/write mode supporting ICODE EPC UID/ EPC OTP
• Read/write mode supporting ISO/IEC 18000-3 mode 3/ EPC Class-1 HF
5.PN532
The PN532 module supports six protocols/operating modes, including NFC. It supports three serial communication interfaces: SPI, UART, and IIC. It is relatively inexpensive, costing less than 10 yuan. It supports the following operating modes:
• ISO/IEC 14443A/MIFARE Reader/Writer
• FeliCa Reader/Writer
• ISO/IEC 14443B Reader/Writer
• ISO/IEC 14443A/MIFARE Card MIFARE Classic 1K or MIFARE Classic 4K card
emulation mode
• FeliCa Card emulation
• ISO/IEC 18092, ECMA 340 Peer-to-Peer
• Reader/Writer mode supporting ISO/IEC 14443-A up to 848 kBit/s, MIFARE
• Reader/Writer mode supporting ISO/IEC 14443-B up to 848 kBit/s
• Reader/Writer mode supporting JIS X 6319-4 (comparable with FeliCa scheme)
• Supports reading of all NFC tag types (type 1, type 2, type 3, type 4A and type 4B)
• Reader/Writer mode supporting ISO/IEC 15693
• Reader/Writer mode supporting ISO/IEC 18000-3 Mode 3
• ISO/IEC 18092 (NFC-IP1)
• ISO/IEC 21481 (NFC-IP-2)
• ISO/IEC 14443-type A Card emulation up to 848 kBit/s
PN5180
The PN5180 is the best full-protocol module supporting NFC on the market [5]. The PN5180 ensures maximum interoperability for next-generation NFC mobile phones. The PN5180 implements high-power NFC front-end functionality, achieving EMV compliance at the RF level without the need for additional external active components. It is relatively inexpensive, costing less than 30 yuan. It supports the following operating modes:
• Reader/Writer mode supporting ISO/IEC 14443-A up to 848 kBit/s, MIFARE
• Reader/Writer mode supporting ISO/IEC 14443-B up to 848 kBit/s
• Reader/Writer mode supporting JIS X 6319-4 (comparable with FeliCa scheme)
• Supports reading of all NFC tag types (type 1, type 2, type 3, type 4A, and type 4B)
• Reader/Writer mode supporting ISO/IEC 15693
• Reader/Writer mode supporting ISO/IEC 18000-3 Mode 3
• ISO/IEC 18092 (NFC-IP1)
• ISO/IEC 21481 (NFC-IP-2)
• ISO/IEC 14443-type A Card emulation up to 848 kBit/s