How to send AT commands by SMS?

 1. First, open setting software, view the command password

open setting software, view the command password

open setting software, view the command password

2. SMS format

            usr.cn#AT+command

For example: usr.cn#AT+VER

           usr.cn#AT+APN

SMS format,How to send AT commands by SMS

3. The AT commands :

https://www.usriot.com/download/GPRS/USR-GM3-AT-Command-Set_V1.0.2.pdf