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

Originally, they were placed on a tray, and a ruler made it from print onto carbon paper. The paper receipts were mailed to the credit card companies. For a long time after that, they worked over phone lines.