输出消息比 TCP/IP 流中的原始数据短 4 个字节。

The output message is four bytes shorter than the original data in the TCP/IP stream.

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基于TETRA数字集群移动通信系统开发的TETRA终端，通过数据业务可以发送和接收状态消息和短数据业务消息，利用短数据业务完成终端导航定位功能。

Terminal based on TETRA digital trunking mobile communication system could send and receive status and short data service message, and achieve navigation and location through short data service.

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