I want to build a checkout computer program for store owners. I'd like to be able to figure out the total price in the program, send that amount to a credit card reader, have the reader carry out the transaction, and then report to my application that the transaction was successful or failed.
Is there a standard for communicating that information with the credit card reader?
I have done a lot of googling and haven't found much any useful information. I know there are a bunch of processors that want to handle payment for you, but I don't want that. I just want to be able to send the amount to the reader from my computer program, and get back success or failure, and let the merchant set up their own payment stuff.
Yes, there are standards. There is a ZVT protocol developed in germany, then the OPI protocol (Open Payment Initiative) developed by Wincor Nixdorf, and VEZ, a standard in Switzerland. All these protocols are documented and work with certain terminal manufacturors and in certain regions. There is also an upcoming SEPA standard for a POS-to-card terminal communication, but it is unclear if terminal manufacturors will implement it.