I would like to know how the communication between my gym card and the checking point works.

I bought an ACR122U reader, but it seems that I can't read my card with it, the card is not recognized as something readable with that adapter. The card hasn't the black stripe that suggests that it is a magnetic one. When I do the check-in in the gym I just lay the card over the checking point for 1 second.

How do I know which type of card it is? Which usb device should I buy in order to see how the communication works and make some read/write operation over the card?

  • I'd look at the gym's reader, instead. Or ask the gym what program they use to program the cards. That will tell you.
    – schroeder
    Jun 24, 2020 at 21:22
  • @schroeder Usually people who you don't have so much confidence with, are not happy to answer this kind of questions :S. I wish I could figure out by myself what technlogy are they using.
    – ScTALE
    Jun 24, 2020 at 21:28
  • I don't agree at all. And it does depend on how you ask. "Hey, I was looking at using something like these cards for a project I'm working on. What's the software called that you use to program these?" works a lot better than "I demand to know what card model and type you use!!!1!1!!"
    – schroeder
    Jun 25, 2020 at 10:25
  • That's called social engineering :)
    – Kaymaz
    Jun 25, 2020 at 18:03


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