This integration will keep your customers on your WordPress website at all times and won't send the customers away to a payment page outside of your website ever.
See the First Data API documentation for installation, activation and setup instructions in order to use the gateway correctly.
Features of this WordPress Shopping Cart Plugin Extension
Configure the First Data API payment gateway according to your needs. Set the title, store ID, install the SSL PEM and set the mode.
Customers will fill in their credit card details on your website and a redirect interface will process the transaction while keeping the customer on your website.
A secure, SSL connection is made with First Data to send/receive data regarding the payment with the use of an SSL PEM file.