说明：  用软件调试助手进行GSM模块AT指令调试步骤的总结，经验！！我是在这个基础上掌握GSM模块进行GSM模块和单片机的通信数据传输。
(Software debugging assistant GSM module AT commands to debug a summary of the steps, experience! ! I am a master on the basis of GSM module GSM communication modules and single-chip data transmission.)