Essentially, I would have multiple "slots" where cards would be placed, where each card would be equipped with an NFC tag, that would then be read. The information would be sent to a server with wireless internet, so, either WiFi or using a SIM card or something similar.
Why not number slots 0-7 and use an 3-bits of an 8-bit port to read which slots are populated... that scan could then additionally used (if card is found) the other 5-bits to represent the card capability. A look-up in EEPROM (or PROGMEM flash) could provide communication info. Something like the old IBM PC ROM space but using solder bridges (switches) to provide data. This could be enhanced by future optical or RFID capability. But I think the POC should be simple... you are not working with a lots of RAM resources.
Ray
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