The Research And Realization Of The Key Teconologies Of The Distance Multimedia Combined Services System

Now with the development of science and teconology, we have entered into the information society and the pure voice service offered by the traditional Public Switched Telephone Network (PSTN), which is used to be the first choice for communication, now can not meet the needs of people who long for multimedia informations. The multimedia teconology gives us more choices and it also lays the foundation of multimedia communication. In the meantime, the development of IP network offers a good support for the multimedia communication while people could get information of words and images and even interactive audio and video and data though the Internet which shortens the distance between people and advances the development of the economy and society. In recent years, with the popularity of IP network, the multimedia applications have became more and more popular like multimedia video conference, distance learning, distance medical treatment, distance call center and so on.In this thesis, a method of combining the traditional PSTN with IP network is adopted to offer distance multimedia combined services which allow people to get information of audio,video and data using telephone or computer.The features of the multimedia information and the special requirements of the multimedia communication are analyzed in the first part of the thesis and then the related technologies of the multimedia communication based on IP network are researched including the multimedia communication protocols, communication modes, the Quality of Service (Qos), the data compression and coding and the mulimedia database. Based on the researches above, a distance multimedia combined services system based on the combination of PSTN and IP network will be put forward which offers the service of audio communication though PSTN and video and data communication though IP network(including white board,text chat, etc). The realization process of the system is specified in the next part of the thesis including the audio communication functions based on PSTN achieved with the benefit of call center technology and the video and data communication functions based on IP network using NetMeeting. The question of storage and withdraws of the multimedia information from the database will be discussed at last.