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The exchanges behind a payment-card tap

The card and terminal communicate, transaction-specific data help authenticate the payment, and an online transaction asks the issuer for approval. Approval is only one stage in the broader payment process, and different payment systems do not all follow an identical route.

3–7 min

Questions you could explore

  • What is the difference between checking the card and deciding whether to approve the purchase?
  • Which participants take part between the card reader and the institution that approves a purchase?

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Computers and AI

Why can a damaged QR code still work?

A scratch or stain does not always stop a QR code from being read. Its stored information includes redundancy, but that does not mean any part of the image can be covered without consequence.

3–5 min

Why can a damaged QR code still work?

Computers and AI3–5 minA scratch or stain does not always stop a QR code from being read. Its stored information includes redundancy, but that does not mean any part of the image can be covered without consequence.

Computers and AI

How does a website name become an internet address?

You remember a website by its name, while the network needs an address for the connection. DNS supplies that translation, sometimes from a saved answer and sometimes by asking other servers.

4–5 min

How does a website name become an internet address?

Computers and AI4–5 minYou remember a website by its name, while the network needs an address for the connection. DNS supplies that translation, sometimes from a saved answer and sometimes by asking other servers.

Computers and AI

Same emoji, different picture

The same emoji can arrive with a different expression or style from the one you saw when sending it. Unicode identifies characters and sequences, while software platforms choose artwork and decide what their versions support.

2–3 min

Same emoji, different picture

Computers and AI2–3 minThe same emoji can arrive with a different expression or style from the one you saw when sending it. Unicode identifies characters and sequences, while software platforms choose artwork and decide what their versions support.

The exchanges behind a payment-card tap | Speech Topic | speaking.app