Reading and Writing RFID Cards
How EM410x cards work and how to read, clone and write IDs with the card reader.
EM410x cards are the simplest kind of RFID tag — they hold a single read-only ID and broadcast it whenever a reader powers them. That simplicity makes them easy to understand and easy to clone, which is exactly what this reader is for.
How the ID works
Each card has a unique ID written as a series of hexadecimal digits. When you hold it near a reader, it transmits that ID. The reader just needs to receive it and turn the signal back into digits.
Reading a card
Place the card on the reader and run the read command. You’ll see the ID appear
on screen — something like 0F0362A1B9. Keep it: that hex string is the card,
for all practical purposes.
Cloning a card
To clone, write the same hex ID to a blank card:
- Read the original and copy its ID
- Place a blank card on the reader
- Write the ID to the blank card
- Verify by reading the blank card again
Good to know
- EM410x is a legacy format with no encryption. It is not secure access control.
- Don’t clone cards you don’t own or have permission to copy.
- Always keep a log of what you write — it makes debugging a lot easier later.
The reader saves every session to a CSV file, which is the fastest way to keep track of a pile of cards without losing your mind.