How do Debit/Credit cards know how much money they should have? Especially before the Internet.

Question

When I slidey debit card, how does the card reader know if there is money on it?

I understand nowadays that the card reader probably just asks over the Internet how much money the account has, but debit cards are older than the Internet, so what did they do back then?

In: Technology

Answer 1

Same thing over telephone lines. And it’s also why Credit Cards were invented first – because the banks would charge you at the end of the month, instead of halting the transaction to check your balance.