system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The proliferation of credit cards happened before the proliferation of the internet. How did credit cards work before the internet?
gpt
Stores would “run” a card by using a small machine that made an imprint of the card number on paper and then they’d send those forms to the credit card company for billing. 

The credit card company would pay the store and then bill the customer. 

But then they started using phones to relay the account number to ensure the credited amount would be authorized. 

And then POS terminals got connected to the internet and the system modernized to what we know now.