In accordance with the EMV Contactless Specifications, these circles indicate the state of contactless transactions:
- First circle from the left blinking: The contactless reader is idle.
- First circle constantly 'on': The terminal has received the payment request and the contactless reader is ready to read a card.
- All four circles 'on': The contactless reader has read the card. A beep will sound, to indicate the card can be removed.