AT指令，用于GSM通信模块，可以发短信，打电话，接电话，上网等，我们的手机差不多也是用这个。-AT commands for GSM communication module, you can send text messages, phone calls, phone, Internet, etc., we also used the phone about this.

详细的GSM通信协议，以及AT指令说明，对于短信猫开发很有帮助。-Detailed GSM communication protocols, as well as descr iption of AT commands for SMS cat development helpful.