cellular_data_communication_system

1.The cellular digital packet data(CDPD) system is a wireless packet communication system based on analog cellular telephone networks.
蜂窝数字分组数据（CDPD）系统是基于模拟蜂窝电话网的无线分组数据通信系统。
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2.Second generation mobile communication system (2g) is digital cellular system which can provide low-speed data business.
第二代移动通信系统(2g)是数字移动系统，能提供低速率数据业务。
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