How did they know back when the credit card machines were manual that the card was still good?

Question

I know that for really big amounts they called the credit card company. But did they also do it for small amounts of $10-$20? And if so how did it work in a Taxi when there were no mobile phones?

In: 1

Answer 1

Back in 83 there was apparently a $25 threshold, below that and most retailers didn’t call/verify or do the telecheck thing. (not sure when that came out)

Mom ran up thousands on a couple of cards (that were already in default) by keeping every individual purchase below $25.

*fun facts from my fscked up childhood…