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?