Diagram of an Onus installment transaction flow between POS and HOST

Before describing the Onus Installment process, it would be more accurate to first answer the question "What is an Onus transaction?"

An Onus transaction is the term used when the acquirer and the issuer are the same institution, meaning the transaction is processed through that same institution. For example, a transaction made with a card issued by Bank X on a POS application belonging to Bank X. There are many more examples like this.

When the transaction described above is completed in installments, it is called an Onus Installment transaction.

So, how are Onus installment transactions carried out?

Institutions can offer installment options for their own cards directly through their POS applications, or they can also apply installments after the transaction, without offering an installment option through the application.

The parts we will be covering here are the ones carried out by offering an installment option through POS applications.

In order to perform installment transactions with Onus cards, the flows and specs to be developed between the HOST and the POS must first be established. Once the flow and specs have been established, the following points need attention:

  • Sending the installment information to the HOST in the POS's 200 message,
  • Building the 800-810 inquiry messages between the POS and the HOST (managed via MCC check and/or inquiry message),
  • If installment information is not already held in the MCC tables, developing screens to maintain installment data separately for individual and commercial transactions,
  • Adding installment authority to the Onus tables within the issuer data,
  • Setting up commission and value-date information for Onus installments in the merchant's working conditions field,
  • Adding installment authority to the terminal authority field,
  • Managing the minimum and maximum number of installments,
  • Adding installment information to transaction and end-of-day receipts (slips) in POS applications,
  • Developing support to correctly reflect installment transactions made on the POS side to card statements,
  • Determining which transaction types will support Onus installment transactions, among many other important points.