In order for the POS terminal to display the transaction type and amount on the display before a card is presented to the terminal for contactless payment, a wakeup should be sent to the terminal.
This is automatically done via the menu, but does require that the menu is in the same local network as the POS terminal.
If the POINT_OF_SALE payment was started by the merchant via de API using the Start Payment endpoint, then the merchant is responsible for sending the wakeup.
The wakeup is a TCP connect to the ip address and port that is returned in the response of the Start Payment. Note that this ip address is the address of the terminal on the local network.
Merchants have to be able to provide the shopper a paper copy of the transaction result as it is the shoppers proof. The use of certain cards can demand a signature on the receipt as a part of the authorization. The receipt is needed in case of a dispute.
There is also a receipt to proof that the shopper canceled the payment on the POS terminal after tapping or inserting the card.
Thus, there are one or two receipts: one for the shopper, and one for the merchant that must be signed by the shopper.
If a POS terminal with printer is used these receipts are automatically printed by the terminal.
If a POS terminal without printer is used then the receipts can be printed from the menu, or the shopper can request the receipt to be emailed.
If the POINT_OF_SALE payment was started by the merchant via de API using the Start Payment endpoint, then the merchant is responsible for providing the receipts to the shopper, and if applicable letting the shopper sign the merchant receipt. These receipts are available via the Order Details endpoint when the payment has the status AUTHORIZED or CANCELED.