With the API SDK / API Seat option customers are able to develop and implement 3rd party interfaces into C-Soft for applications such as CAD, AVL and other systems. It utilizes an encrypted connection and user authentication to ensure data reliability. The API SDK requires a Non-Disclosure Agreement (NDA) with the third party developer. It comes with documentation and a simulator to help in interface development. Telex Radio Dispatch engineering recommends that anyone purchasing the SDK also purchase a 2-line version of C-Soft and the corresponding API Seat in order to facilitate total testing of any solution developed. The API is required in order for C-Soft to talk to a 3rd party product where the SDK has been used to develop an interface and is sold on a per seat basis.