Payment Gateway post-purchase FAQ

Categories E-commercePayment Gateway

What is Preauth(orisation)?

Preauth is the process of determining whether the funds are available on a credit card before completing a transaction. This also allows an online retailer to process a customer's transaction only when the item has been shipped or to cancel transactions without having to go through the entire refund process.

Note: Only St George allows preauth with our payment gateway. To enable preauth transactions on a gateway, you will need to first contact the vendor of the merchant facility (St George) to have it switched on at their end. Once this is done, the payment gateway should start accepting preauth transactions.

The command 'completion' requires the preauthnum field. Where do I get the value for this field from? Is this the transaction number received from a preauth command?

Yes. The format and content of the pre-auth and completion commands are displayed on Page 5 of the Payment Gateway document, attached to this article.

I've been sending preauth commands and the response I get is 'NOT SUPPORTED'. Is this due to the invalid card number 4111111111111111 or is it due to something else?

It could be either. The client (Merchant) needs to get the bank to setup the ability to do pre-authorisation, once they have done this, the bank will tell us and we will make a slight change to the setup. Also you need to submit the card number and the transaction number to complete the pre-auth.

Can you please give me the complete list of response codes (ie. W6, 31, etc) and their definitions?

There are quite a lot of these and we analyse the majority of them before they are passed to you as they are system level errors that can only be action-ed by our systems administrators. The two responses you need to be concerned with are “approved” and “declined”. All response codes that you will see do have an accompanying response text.

How do I analyse the currency to the gateway server?

Using the, you simply specify the currency after the AMOUNT variable, e.g. “AMOUNT=1000AUD” will deduct $10AUD or “AMOUNT=1000USD” will deduct $10USD. Note that the decimal point should be ignored. If using the ASP.NET method, specify the currency in the CURRENCY field as described in Programming in ASP.NET on Page 9.

AMEX, DINERS and JCB support

AMEX, DINERS and JCB card support isn't automatically enabled on the Merchant account with your bank. Please follow the instructions below to enable support for these card types with your merchant bank account and your Payment Gateway service.

  1. Contact AMEX, DINERS and JCB card vendors.
  2. Request authorisation to make transactions on those cards. The vendor (AMEX, Diners or JCB) will supply you with appropriate authorisation agreement and letter which you will need to pass onto your merchant vendor (your bank).
  3. Contact the appropriate merchant vendor (St. George or NAB).
  4. Supply the authorisation letter from the card vendors to the merchant vendor, who will then modify your merchant account to accept payments from those card types.
  5. Contact us to advise of what changes have been made to your merchant account and request that we update the Payment Gateway service appropriately.
  6. We will make the necessary changes and advise you by return e-mail.
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