The SAT (SIM Application Toolkit) The SAT (SIM Application Toolkit) provides a flexible interface through which developers can build services and MMI (Man Machine Interface) in order to enhance the functionality of the mobile. This module is not designed for service developers, but network engineers who require a grounding in the concepts of the SAT and how it may impact on network architecture and performance. It explores the basic SAT interface along with the architecture required in order to deliver effective SAT based services to the handset.