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

Before the Internet, credit cards were rarely used for small expenses and when you bought something expensive, the store would call the bank/CC company on the phone to check the balance.

There were often minimum amounts to use the card. I remember $25 minimum. It varied quite a bit over time.