How to create a payment module?

[josedanielestrada]

I would like to know how to create a payment module from the beginning.

[Kim]

Step one is to get the documentation from the Payment Processor.

[josedanielestrada]

Where i can find that documentaction?

[superprg]

Which payment processor you want to connect zen-cart to?
Let us say authorize.net
Then you can get it here
http://www.authorize.net/resources/documentlibrary/

[josedanielestrada]

Tnxs for the answers, they were very useful.
Now i am modifying authorize.net, it sends many values to the server. The question is, what's the flow of the data (file processing and server response)?