s can be seen. Additional information as text or pictures is projected on the glasses depending on the actual context. You get the sound via the earplugs. When you for instance walk in a new place you can get relevant information of where you are or about buildings or landmarks that you pass. Even if spectacular new applications can be foreseen, a more immediate and important application area is that of support for disabled persons to compensate for a lost or degraded sense or ability to move. Conversational Multimedia Conversational multimedia is bi-directional (interactive) communication (e.g. for video telephony) by means of real-time end-to-end information transfer from user to user. For conversational multimedia calls the following functions require state and functions in the call session server: Support for enhanced addressing (Enhanced because of multimedia) Enhanced security (Enhanced because of multimedia) Enhanced charging (Enhanced because of multimedia) Supplementary services Note that the streaming multimedia (e.g. video streaming) can be transparent to the core network, i.e. no call session server is needed. What are 'Web Services'? Web services are briefly explained in Section 3.13. A more detailed explanation is given in Appendix 1. Services 5.1.4 HISTORY AND SUCCESS FACTORS History Historically voice services have been the main source of telecom income. Even if the data traffic is larger today, globally, voice income is still at least equal because of the different charging methods between voice and data. Since fixed and mobile voice is maturing in many countries, the development of the telecom sector will depend more and more on non-voice services or enhanced voice services including multimedia. Long-term forecasting of service (phone calls) development is another historical feature. It goes without saying that this is more or less impossible in a multiple service environment with considerable uncertainty about the market for individual services. Success Factors: Network In this less predictable