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

The Internet in its current form, private citizens using computers and phones to view Web sites, goes back to the 90s, and other forms of it are older than that. Banking computers were using phones to talk to each other in the 70s. Debit cards aren’t too much older than that.