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EMV Approved & Cancelled

note

In this web sequence diagram, Payter details the core flow of an EMV payment which is successfully authorized, but due to either a vend failure or an error, no vend takes place. In this case, the Authorization must be voided to return the reserved funds to the cardholder.

Flow​

Payment Flow DiagramPayment Flow Diagram

Comments​

  1. When using Always Scanning there could hours or days between these two events.
  2. The controller needs to Decide to Authorize. If they are choosing to accept RFID cards then these follow a different flow, with the local controller either checking online itself, or comparing to a whitelist of card ID's. Even where no RFID cards are accepted, this decision is required.
  3. The controller needs to interpret the Authorization outcome - in this case it is Approved, but logic for handling Declines should be implemented.
  4. Vend Failure occurs. Examples of this include:
    • An EV Charger which fails to start a charge
    • An EV Charger where the driver does not plug their vehicle in
    • A vending machine which was/is out of stock of the product selected
    • A smart fridge where no product is taken
  5. A "Void Session" is sent to cancel the original authorized amount. Without this message, the funds will remain reserved in the cardholders account for several days/weeks.
Minimum Commands

Integrators need to implement the following commands as an absolute minimum in this approach:

  • Start Session
  • Auth Session
  • Cancel Session