| The development of network technology and multimedia technology has greatly improved the communication technology of integration, digitalization, intellectualization and personalization, which makes it possible to realize integrated services of audio, data, video and so on, on a single network platform. Therefore, under such a background, the IP telephony technology, which integrates network technology and multimedia technology, has appeared and made fast development. Now it has become a strong competitor in the field of audio communication technology. Apart from those advantages of using packet switching, improving the efficiency of the channel and lowering the communication cost, using the IP telephony technology is easier to realize the expansive services and the integration with the multimedia technology, which makes it advantageous among telecommunication fields and prosperous in the future.In view of the development of IP telephony, the working principles and key technology of IP telephony are firstly discussed and summarized in this paper. The standard about VoIP, H.323, is described in detail. According to H.323 standard an IP phone based on DSP was developed. The method and process of the design and development of the terminal are introduced in the paper, including voice processing module, net module, user interface module, and so on. Testing shows the terminal meets the requirements quite well. Based on the development and testing, the influence of delay, jitter and packet loss on the voice are analyzed in the paper. |
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