Advanced loyalty

The possibility to read one or more cards before the payment is actually made, makes it possible to know the customer and give a discount on the sale being made. With the possibility comes just a little bit more complexity and logic around messages.

Easy flow reading card before payment request

sequenceDiagram
participant POS
participant Terminal
    POS->>Terminal: EnableService Request StartTransaction
    Terminal->>POS: EnableService Response success
    activate Terminal
    loop open all readers for card read
        POS->>Terminal: CardAcquisition Request
        Terminal->>POS: CardAcquisition Response
        Note left of Terminal: Response contains<br/>CNA,<br/>Masked PAN,<br/>Card type,<br/>Card product name
        Note left of Terminal: Terminal shows "please wait"
    end
    POS->>Terminal: Payment Request
    deactivate Terminal
    Note right of POS: Normal procedure for payment request.<br/>Last payment card read is used

The messages EnableService and CardAcquisition are key to this feature, but when aborting in different situations different messages are used depending on state. A CardAcquisition is aborted using an AbortRequest but the enabled service is aborted using the EnableServiceRequest AbortTransaction.

Abort while waiting for a card

sequenceDiagram
participant POS
participant Terminal
    POS->>Terminal: EnableService Request StartTransaction
    Terminal->>POS: EnableService Response success
    activate Terminal
    POS->>Terminal: CardAcquisition Request
    POS->>Terminal: AbortRequest
    Terminal-->>POS: Http response 204
    deactivate Terminal
    Terminal->>POS: CardAcquisition Response
    Note left of Terminal: Terminal shows transaction aborted
    Note left of Terminal: Terminal goes to idle state

The enabled service Transaction state lasts from the EnableService response until it is aborted or a PaymentRequest is sent. During that state several cardacquisitions may be issued, but if abort is desired after a card acquisition response there is no ongoing request and the state is terminated by the EnableServiceRequest AbortTransaction

Abort sequence after card has been read

sequenceDiagram
participant POS
participant Terminal
    POS->>Terminal: EnableService Request StartTransaction
    Terminal->>POS: EnableService Response success
    activate Terminal
    POS->>Terminal: CardAcquisition Request
    Terminal->>POS: CardAcquisition Response
    POS->>Terminal: EnableServiceRequest AbortTransaction
    Terminal->>POS: EnableServiceResponse success
    deactivate Terminal
    alt payment card was read
        Note left of Terminal: Terminal shows transaction aborted
        Terminal->>POS: PrintRequest with receipt information
    end
    Note left of Terminal: Terminal goes to idle state

EnableService

Request

1
2
3
4
5
6

<SaleToPOIRequest>
  <MessageHeader ProtocolVersion="3.1" MessageClass="Service" MessageCategory="EnableService" MessageType="Request" ServiceID="3" SaleID="1" POIID="A-POIID" />
  <EnableServiceRequest TransactionAction="StartTransaction">
    <ServicesEnabled>CardAcquisition</ServicesEnabled>
  </EnableServiceRequest>
</SaleToPOIRequest>

Response

1
2
3
4
5
6

<SaleToPOIResponse>
  <MessageHeader MessageClass="Service" MessageCategory="EnableService" MessageType="Response" ServiceID="3" SaleID="1" POIID="A-POIID" />
    <EnableServiceResponse>
      <Response Result="Success" />
    </EnableServiceResponse>
</SaleToPOIResponse>

Next request following a successful EnableServiceResponse for TransactionAction StartTransaction, is CardAcquisition or EnableService with TransactionAction AbortTransaction.

CardAcquisition

Request

1
2
3
4
5
6
7
8
9

<SaleToPOIRequest>
 <MessageHeader ProtocolVersion="3.1" MessageClass="Service" MessageCategory="CardAcquisition" MessageType="Request" ServiceID="4" SaleID="1" POIID="A-POIID"/>
 <CardAcquisitionRequest>
  <SaleData TokenRequestedType="Customer">
   <SaleTransactionID TransactionID="1212203" TimeStamp="2023-10-18T12:12:20+02:00"/>
  </SaleData>
  <CardAcquisitionTransaction PaymentType="Normal" TotalAmount="0"/>
 </CardAcquisitionRequest>
</SaleToPOIRequest>

Response

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

<SaleToPOIResponse>
 <MessageHeader MessageClass="Service" MessageCategory="CardAcquisition" MessageType="Response" ServiceID="4" SaleID="1" POIID="A-POIID"/>
 <CardAcquisitionResponse>
  <Response Result="Success"/>
  <SaleData>
   <SaleTransactionID TransactionID="1212203" TimeStamp="2023-10-18T12:12:20+02:00"/>
  </SaleData>
  <POIData>
   <POITransactionID TransactionID="8778880092" TimeStamp="2023-10-18T10:12:26.625Z"/>
  </POIData>
  <PaymentInstrumentData PaymentInstrumentType="Card">
   <CardData PaymentBrand="01,Mastercard Debit" MaskedPAN="516815******9659" EntryMode="Contactless">
    <PaymentToken TokenRequestedType="Customer" TokenValue="6FD955C23A48A041D881003CDBF836DC59F89CE0ECA8288129696CDF9BB8B8DD67F233"/>
   </CardData>
  </PaymentInstrumentData>
  <LoyaltyAccount LoyaltyBrand="01,Mastercard Debit">
   <LoyaltyAccountID EntryMode="Contactless" IdentificationType="ISOTrack2" IdentificationSupport="LoyaltyCard"/>
  </LoyaltyAccount>
 </CardAcquisitionResponse>
</SaleToPOIResponse>

Proceed after card read

Following a successful CardAcquisitionResponse the terminal will show “Please wait” and any of the messages EnableServiceRequest AbortTransaction, CardAcquisitionRequest, PaymentRequest, DisplayRequest or InputRequest is feasible. If the amount is still not available a DisplayRequest with text set to continue_processing will exit the enabled service state and let the terminal proceed with PIN dialog if appropriate.

Proceed with PIN dialog if appropriate

sequenceDiagram
participant POS
participant Terminal
POS->>Terminal: CardAcquisitionRequest
Terminal->>POS: CardAcquisitionResponse Success
Note left of Terminal: Terminal shows "Please wait"
POS->>Terminal: DisplayRequest "continue_processing"
alt Contactless 
Note left of Terminal: Terminal shows "Awaiting amount"
else Chip inserted
Note left of Terminal: Terminal shows "Enter PIN"
end