As an alternative to static SIM toolkit applications with a fixed pre-installed menu, some operators opt for dynamic SIM toolkit, where the menus and user dialogs are generated on the fly based on information provided by a central server. SIM applications that provide this functionality are generally referred to as SIM browers or µ-browsers.

The Wireless Internet Browser (WIB) specified by SmartTrust was the first succesful such µ-browser. The SIM Alliance has on their side defined an alternative browser named the S@T browser.

The S@T specifications are open and therefore allow the operator a choice of supplier for both the S@T gateway and S@T enabled cards.

Logos offers a SIM OS with an integrated S@T browser as well as a cost efficient S@T gateway.