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faq:troubleshooting_msg_invalid_check_digit

Parent Article: Troubleshooting Credit Card Results From Mercury Payments

Invalid Check Digit

This is an error message that shows on the slip reciept. This message only happens when you type in a credit card manually. It means that you mistyped the number and then requested and authorization.

Does this message come from System Five, the processor, Mercury Payments, or elsewhere?

This is a DSIClientX Specific (TCP/IP> Message from Data Cap. There are messages from System Five before you request the Authorization that also tell you the card was mistyped. This message is “Invalid Checksum”. It shows up in black text on screen in the green authorization window within System Five.

Why does it happen?

Since the card number is not correct your processor will not process it. There is a formula used to calculate the last digit of the credit card. This digit is like a key that only works with the customers credit card. Since there is a formula, you don't get problems where when someone else with a simular card number transposes 2 digits of the credit you don't get charged for their purchase. It is not 100% perfect, but is very reliable.

Who does this apply to?

This only applies when you manually enter a card number for authorization.

What causes this error?

  • A Mistake in manual entry of a card number.
  • Please note there is a situation where if a card swipe is not configured correctly with the % prefix and you get a bad swipe this message can appear.

When does it happen?

When you can't swipe the card and have to enter the card number manually.

Can it be prevented?

Yes, easily.

If so, how can it be prevented?

This problem can easily be prevented by double checking the credit card number before typing it in.

Is there any documentation available on this error?

No external references found at this time Oct 25, 2010-cm

faq/troubleshooting_msg_invalid_check_digit.txt · Last modified: 2010/10/26 10:11 (14 years ago) by cliff