I'm using the RDM6300 125kHz reader module in combination with Arduino Uno to read my tags.

The tags themselves have their ID as a label. When I then try to read the cards, I receive another ID as the indicated label. For example:

Tag label: 0009471985

Reader Output: 0x85009087F163 = 146237471322467

But when I ignore the first and last byte, the ID is correct:

Reader Output: 0x85009087F163 = 146237471322467

Ignoring first and last byte: 0x009087F1 = 9471985

This happens with all my tags I read. But the bytes change for every tag, so they can't symbolize the beginning and ending of the transmission. When I use an other Chinese reader, it outputs me the correct ID as decimal numbers. Should I now ignore those two bytes, when creating access control and focus on the ID indicated on the tag? And what do those bytes represent? Are they a checksum?

Thank you!


Yes, it's safe to ignore those bytes, unless you plan on using them. They are the header and footer respectively. The checksum is in the first two bytes.

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