Value added service for mobile communications

The highly intensive race among GSM operators for their market share have created a rich environment for an advent of many services beyond core services, meaning just making calls and sending SMS which will refer to it as value added service or VAS. A typical example of VAS: when a mobile user is willing to know weather forecast so he or she get into an application stored inside the SIM card, prompted to input the city of interest and get information provided by some server. This kind of services obviously generates an additional Average Revenue Per User ARPU. In this paper we will discuss how VAS is implemented, we will also make a discussion on Enhanced short message service ESMS as a key element for the remote management of SIM cards i.e. sending a specific command to SIM cards to do configurations and creating and managing VAS applications remotely. We will see how SIM cards can perform a proactive commands for the mobile equipments and become no more slaves to them. Here, the term SLAVE means the logic relationship of master-slave where in older GSM services, the SIM cards main function is to respond to the commands given by the mobile equipment with simple data. These commands called Application Data programming Units or ADPU commands.