In the application of remote multimedia surveillance based on PSTN(Public Switching Telephone Network)

one of the key technologies is the compression of video and speech data stream at a ratio as high as possible

while the quality of the video and speech are ensured for the surveillance application; Other key technologies are such as the real time processing of the compression of video and speech data stream. The PSTN based remote multimedia surveillance system

which is introduced in the article

compresses the video data stream based on the protocol H 263 and speech data stream based on the protocol G 723 1. The article first introduces the architecture of the system. Then after a short introduction to the H 263 and G 723 1 protocols based video and speech compression algorithms

some considerations with the video and speech compression are discussed for the requirements of the remote multimedia surveillance application. Further

the design and realization of the remote surveillance terminal

which is the key part of the system

are introduced with details. Also the key technology and method of the real time processing of speech and video compression based on DSP(Digital Signal Processor) are presented. As a conclusion

the main performances of the system are reported at the end of the article.