This from their web page
Our Level 3 API (Application Program Interface) offers clients and developers the ability to integrate a powerful B2B / B2G payment gateway into proprietary operations software. Our API is comparable to Authorize.net and PayPal except that it is capable of passing Level 3 data for the best available commercial card Interchange rates. Once integrated, your software application will be able to process real-time Level III transactions, securely store customer payment data, and much more.
This solution is typically used in high volume situations where business processes require transactions be entered into and managed by you existing POS, accounting, ERP, or CRM systems.