| Now, with the proliferation of broadband network and the charges fall, the Internet has become essential part of our life and work. Web applications are not only remain in the primary stage like information search, but also gradually extended to all aspects of daily life. VoIP (Voice over Internet Protocol) technology is a very popular part of those applications. Through the VoIP technology, people can use Internet to transmit voice and other media conveniently by very low communication costs. And with the development of network bandwidth and real-time voice transmission technology, the big problem of VoIP application: voice quality, has been large improved. In this way, the VoIP has become a important part of voice communications area.Based on this trend, the paper proposes a new VoIP applications running on embedded devices and this is a real project which has been developed at author's practice stage. To compare with other solutions, this project has developed on embedded device, so this project could work without PC and run independently. The call control module in this system has based on the popular SIP protocol as call control protocol to ensures compatibility with other devices and extensibility. Application software has been designed using a modular solution, and using message mechanism to control those modules. The realization of main modules based on finite state machine, those could make the code more clear and effective. This architecture could provide a useful reference for the future development of related products.Finally, though the functional test and stability test, we show that this VoIP device has a good protocol compatibility and stability. And we also find out some issues that should be improved and analyzed in the future. |
PDF Full Text Request