system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some card readers at the register seem like they take forever to process (asking debit/credit, double confirming total) and others are done completely in 3 seconds?
gpt
The reader only reads the card.  It has to go thru internet connection to reach the bank to live process the transaction.  If internet at the vendor is slow or being disrupted, the transaction can stall.