Chip and Reader Compatibility in RFID Cards

For an RFID card to work without problems, the card and reader must work on the same frequency and the same standard, and the system must recognise the card. Checking the points below before ordering largely eliminates the risk of an incompatible card.

1. Frequency

A 125 kHz reader only reads 125 kHz cards, and a 13.56 MHz reader only reads 13.56 MHz cards. Some readers support both frequencies; this information is written in the reader's technical document or on its label.

2. Standard and chip type

• 125 kHz: most readers in the field read EM-compatible cards; the 125 kHz cards we sell have TK4100 (EM-compatible) chips.
• 13.56 MHz: the ISO/IEC 14443A standard is common; the system may expect a specific memory structure (e.g. 1K bytes).
• NFC: NFC tags (e.g. NXP NTAG213 and its alternatives) are read by phones; whether an access or payment system reads these cards cannot be known without testing.

3. What does the system use from the card?

Some systems only read the card's unique number (UID); new cards are registered in the system with this number. Other systems write their own data to the card's memory (hotel locks, payment systems); in this case the cards need to be encoded with your system provider's device. Ask your provider which applies.

4. Number format

The card number may appear in different formats on different readers (decimal, hexadecimal, truncated). When registering cards in bulk, knowing which format your reader outputs the number in makes your job easier.

Our recommendation

Contact us with a card from your existing system or the reader model information, or place a small trial order first. Card types: 125 kHz · 13.56 MHz · NFC. For the basics, see the What is an RFID card guide.

You can choose the card that suits your reader on the RFID card types page.

NTAG and MIFARE are registered trademarks of NXP B.V.