Duplicate Transaction System (DTS)


DTS Introduction
Configuring DTS
DTS for LinkSmart and ExpertLink


DTS Introduction

IntelliPay's Duplicate Transaction System solves several possible problems for you, and provides interesting opportunities to improve your risk management related to Duplicate Transactions.

Some Merchant Problems From Duplicate Transactions
Duplicate transactions can be a problem for Internet businesses of all sizes. A successful duplicate transaction will most likely become a chargeback to the merchant when the customer sees their monthly statement and realizes they were charged twice for the same purchase, even if it was an innocent error.
(Excessive Chargebacks can be a problem for you with your merchant account provider. See our report "About Merchant Accounts" for a brief discussion of this risky and possibly expensive problem.)

Also, Duplicate Transactions can be a source of credit card fraud. For Internet merchants who are assuming all risk related to fraud (as detailed in your merchant account agreement with your merchant account provider), having someone with stolen card numbers quickly running many duplicate transactions can be a real problem. If you fulfill your product or service in real-time or automatically, based on a credit card approval, this fraudster can cause mayhem for you.

You might see a duplicate charge in a batch for several reasons:

  • you inadvertently enter a manual charge more than once;
  • your customer double clicks on the Submit;
  • your customer hit Submit again since your site or shopping cart was reacting slowly;
  • or they resubmitted since their Internet connection was slow and confused them;
  • your customer ordered more than one of the same thing;
  • (unfortunately) a credit card thief is on a spending spree.

Most credit card processors and/or bank networks do not provide their merchants with a duplicate control/prevention mechanism.

The Usual Solutions
In the past, if you caught the duplicate on the same day it occurred, but before it settled, you could (and still can) simply Void it from your Open Batch in SAMS. If you or your customer discovered it later, you could use Smart Terminal to issue a credit, and be charged a transaction fee from your merchant account. These steps require some vigilance, as well as some manual steps to control this problem.

However, in Internet or merchant-not-present purchases, you aren't there to do these things.

IntelliPay's New, Customizable, DTS - a Powerful Automated Solution
One of IntelliPay's missions is to develop and provide useful transaction tools and features and to be in constant contact with our merchant customers for feedback about their needs. DTS is a direct response to some of our customers offering online immediate fulfillment of financial and digital products who were having duplicate transaction problems probably related to fraud attempts.

In our DTS beta, one of these merchants is able to block a significant number of duplicate transactions that they believe are fraud attempts, and DTS has saved them thousands in fees and labor costs monthly.

Additionally, the customization features of DTS, along with other ExpertLink features, allow them to vary IntelliPay's behavior on a transaction-to-transaction basis, giving them a very dynamic user experience and enhancing their risk-management procedures remarkably.

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Configuring DTS

The IntelliPay DTS behaves according to the configuration settings in your Secure Account Management System (SAMS) under the Edit Configuration Menu. The configuration controls are easy to understand and include setting DTS to monitor both credits and normal transactions. These configurations affect Smart Terminal, LinkSmart and ExpertLink equally.

You control duplicate charges in the following ways from Edit Configuration settings:

  • Check sales and returns separately.

    In your business, it might be the usual case that sales should not be duplicated, but returns may be because of multiple orders and shipping delays. Or, coincidentally, a repeat customer may return two different items for the same amount on the same card. You need the flexibility to accommodate the variations appropriate to your business.

  • Check just for repeated use of the same card number, or

    You may not want to accept more than one sale against a given card number, regardless of amount, during the duplicate control time period. Merchants who distribute an immediately-available electronic product should consider this issue carefully.

  • Check for repeated use of the same card number and amount.

    To prevent accidental duplicate entry of a single order, you can have IntelliPay check both the card number and amount of a sale (or return).

  • Check for any number of minutes, up to 1440 (24 hours).

    You may only care about catching duplicate requests caused by eager customers double clicking in their browsers. On the other hand, you may want to limit sales to any single card and/or amount to one-a-day.

  • Override the default behavior specified in your configuration on a request-by-request basis in LinkSmart or ExpertLink.

    Suppose that normally you don't object to repeat orders, but during a special promotion you want to allow only one sale per customer. Or, turning the example around, maybe you only want to allow repeat sales for special promotional orders. In either case, you can use request-by-request tags to help you enforce those rules.

If you would like to use the Duplicate Transaction System, your IntelliPay account representative can turn it on for you. You can also ask your IntelliPay provider for access to DTS configuration. Bear in mind that some IntelliPay providers prefer to configure the DTS for your account themselves.
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Using DTS in Smart Terminal

When you have DTS configured and you process a duplicate transaction in the Smart Terminal. A message will appear advising you that the transaction you are processing is a duplicate, at this point you can choose to not process the transaction by resetting the form or click the check box at the top of the page to allow the duplicate transaction to be processed and press the Submit Transaction button again.

DTS for LinkSmart or ExpertLink Users

In general, you can configure DTS in Edit Configuration and proceed with your LinkSmart or ExpertLink coding normally and DTS will automatically check each transaction according to your configuration settings. However, there are two HTML tags that can be used in LinkSmart or ExpertLink to change the behavior of DTS on a transaction-by-transaction basis if wanted.

These settings give you very powerful and dynamic control over DTS and allow you to build a very powerful front end on your side to better serve your customers, or to better fit your business processes.

It's important to understand the use of DUPECHECK and DUPEOK so you get the behavior you want.
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DUPECHECK instructs IntelliPay to check this transaction against the duplicate list when it is sent with the value Y. That is, sending DUPECHECK with the value Y guarantees that IntelliPay will check this transaction, regardless of your configuration.

Conversely, DUPECHECK sent with the value N guarantees that IntelliPay will not check this transaction, again, regardless of your configuration.

As with all transaction control tags, you would typically send DUPECHECK in a hidden field, as follows:

<INPUT Type="hidden" Name="DUPECHECK" Value="Y">

Note that the case of the both the tag name and the value are important.
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DUPEOK is another transaction control tag that tells IntelliPay that a previously-identified duplicate request can be authorized. It should only be sent to IntelliPay in a second request for the same transaction where the first request received a RESPONSECODE of 'S' ("Same"- meaning it's the same as another transaction within the merchant's configured testing period.)

If there was no earlier identical transaction, it's not a "dupe", therefore, DUPEOK set to Y will error. DUPEOK is useful only if there is an earlier approval for the same transaction (based on your configuration settings).


  1. Transaction "A" authorizes normally;
  2. Transaction "B" arrives with the same card number and/or amount and is within your DTS time window. DTS finds the earlier transaction, refuses to authorize the new dupe, and sends you a response of "S" ("S"ame).
  3. Now that you know Trans "B" is a legitimate dupe, you can re-send it with DUPEOK set to "Y", and it will authorize normally.

Note: In the past, sending DUPEOK was harmless for FDC, Nova, Vital, and FTB merchants, because it was ignored by those processors. However, now that IntelliPay performs extended duplicate checking, sending DUPEOK routinely in all requests is no longer harmless.
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The two tags DUPECHECK and DUPEOK may be used together. The following table defines the action IntelliPay takes when both are sent in a transaction request:

Duplicate checking done; if prior dupe, auth; if not, error.
Duplicate checking done; if prior dupe, error;
No duplicate checking done.


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Also see documentation about the Secure Account Management System, and other IntelliPay products from our Documents section.


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