As voice communications is the primary media of communication for human being, it plays a very important role from public switched telephone network to the third generation mobile communications.

话音是人与人之间交流的主要方式，从最早出现公共交换电话网络到现在的第三代移动通信，语音通信是其最基本的功能。

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As voice communications is the primary media of communication for human being, it plays a very important role from public switched telephone network to the third generation mobile communications.

话音是人与人之间交流的主要方式，从最早出现公共交换电话网络到现在的第三代移动通信，语音通信是其最基本的功能。

youdao