The proliferation of credit cards happened before the proliferation of the internet. How did credit cards work before the internet?

Question

The proliferation of credit cards happened before the proliferation of the internet. How did credit cards work before the internet?

In: 155

Answer 1

The sales slip was three copies. Cardstock under two thin paper sheets with carbons. The middle slip was given to customer. At the data center the cardstock was keypunched with account number, date and amount, like a Hollerith card. Your monthly statement came in the mail, and would include a stack of the punched cards you could use to verify your charges.