接收前面的雷达信息，平时没有测速信号时，雷达会定时发射一个连接信号，以检测RF是否连接正常。当遇到测速信号时，雷达会发射特定的代码。-Receiver in front of the radar information, granted that there is no gun signal, the radar will regularly launch a connection signal to detect whether or not to connect the normal RF.