int main(void)
{
char* cmd_str = "AT+CGACT=1,1\r\n"; // Activate PDP context
char* apn_str = "APN name"; // Enter your APN name here
char* user_str = "APN username"; // Enter your APN username here
char* pass_str = "APN password"; // Enter your APN password here
char* conn_str = "AT+NETOPEN\r\n"; // Open network connection
char* ip_str = "AT+CIPOPEN=0,"TCP","example.com",80\r\n"; // Connect to server