sony 351音响串口控制程序！程序本身提供了操作界面，可以切换351的四路输入ABCD，同时也可以增加对声音实现增加、减小、静音等功能。-351 serial control procedures! The process itself provides a user interface that can switch 351 4P ABCD input, but can also increase the voice added, reduce, mute function.

Mobile GPS MD-351 user manual