Here we discuss various RFID / NFC boards as they’re sold on eBay/AliExpress.
RFID vs NFC
What is the difference between RFID and NFC? As far as I have been able to tell, ICs marketed as NFC supports reader to reader communication, while chips marketed as RFID only supper reader to card communication.
Low frequency RFID tags operate between 125 and 150kHz. Many tags are read only, they only transmit an ID code, and that’s it. There are read/write tags available. Apart from animal identification, I haven’t been able to find any standardisation, thus tags use proprietary protocols designed by their manufacturers. As far as boards on AliExpress/eBay are concerned, I have only been able to find read-only boards. Most of the implementations are analogue in nature. Modulation/demodulation is achieved by electronics and the protocol is handled in software.
High Frequency RFID tags operate at 13.56 MHz. Communication with HF RFID is standardised, but there are a number of standards available. There is ISO-14443-A, which includes tags like MIFARE and NTAG, there is ISO-14443-B which includes tags like SRI512. There is JIS-X 6319-4, a Japanese standard, which includes cards like FeLiCa, Finally there is ISO 15693, which includes cards like ICODE. Communication with HF tags is done using dedicated communication ICs. Such an IC may implement a subset of the available protocols.
The NXP MFRC522 is an IC used on popular boards sold on eBay/AliExpress. This IC supports ISO-14443-A and has hardware support for MIFARE encryption. In the same family there is also the MFRC523, which adds ISO-14443-B support. Finally there is the PN512, adds FeLiCa and Active Mode. There is a Chinese clone made by Fudan Microelectronics. They offer the FM17522E. Unfortunately, they only offer a short datasheet, and no user manual. The short datasheet only mentions ISO-14443-A and no MIFARE. This suggests it might not support the hardware assisted MIFARE encryption. However, I haven’t seen any notes of that online. Then there is the FM17550, again, only a short datasheet, no user manual. This one supports ISO-14443-A and ISO-14443-B.
Note that NXP does not recommend the MFRC522 for new designs, and suggests to use the CLRC633 instead.
The CLRC633 is the suggested alternative for the MFRC522. This IC also belongs to a family, with various protocol support. ISO-14443-A, ISO-14443-B, JIS X 6319-4 and ISO 15693 are all possible.
Ultra High Frequency
Ultra High Frequency RFID tags operate between 865 and 928 MHz. The standard covering this family of RFID tags is ISO 18000-6. This standard defined 4 types, A, B, C and D. which was split off to become ISO 18000-61, ISO 18000-62, ISO 18000-63 and ISO 18000-64.