Quick question here regarding Access Control: Is the "beep" from the HID reader when you swipe a blank card, the only way to know if a card is incompatible ?? As far as I know, if you swipe an old 125 KHz card unto a newest 13.56 Mhz reader (or vice-versa) and it does NOT beep: it means you are trying to use an older format card in an incompatible reader.
Background on the case: the integrator abandoned the project and the end user needs to create new credentials for new employees. It seems the card he bought elsewhere are NOT compatible with the HID readers already installed.