ce management, SAT enables an Internet interface for an applica- tion provider to create services based on SMS, OTA SIM File management, and SIM application toolkit. On the wireless network side, the SAT SCS uses the SIM toolkit messaging5, i.e. for secure transport of the web pages. On the Internet side the SAT SCS connects to one or more applications through HTTP. On the terminal side, the SIM card includes a browser that receives web pages from the applications and converts them into SIM application toolkit commands, thus interacting with the user. 9.8.2.1 SAT Service Capability Server Further realization of the SAT will include, e.g. a Service Capability Server (SCS), which we can logically divide into two parts, i.e. the request and the push modules. The SCS receives web pages from the application, converts them into byte code and sends them to the browser using GSM 03.48 for the transport. The difference lies in how the web page is fetched from the application. The request module waits for requests from the browser for a certain web page, fetches the page and returns it to the browser. The push module waits for the application to send a web page to a certain browser, thus the user or the browser does not have to take the initiative but it rather comes from the ap- plication. A web page could either be written in HTML or WML. 9.8.2.1.1 Browser and Menu The browser resides on the SIM card of the terminal. It runs byte code strings and con- verts them into SAT commands. The byte code could be fetched from two places, i.e. they can reside on the SIM card or they could be sent from the SAT SCS. When the browser receives byte code it starts to interpret and convert it into SAT commands. The byte code was originally written in HTML/WML and thus the interpretation can be seen as conversion from HTML/WML to SAT commands. A key part of SIM application toolkit constitutes the menu inserted into the standard menu structure of the terminal. The menu becomes the starting point for the user to ac- cess the web through the