Mifare id card reader reads NFC chip in my SGS4 but the output is always different.

[hellomania]

Hi,
where I work we have these mifare 1k id card readers for access control. I placed my Samsung galaxy S4 with NFC turned on on the reader and the reader recognises it.
I tested it on a USB reader and I see that every time that I place the phone to a reader it transmits different string.
Is it possible that this string stays the same every time?

Thanks for your help.

U