Receive SMS example

Hardware Arduino GSM Shield
2

Hello,

Try to receive sms using AT commands with the next code and sending them via serial monitor (configured CR / NL).

#include <SoftwareSerial.h>
#include <string.h>

char incoming_char = 0;
SoftwareSerial cell(2, 3);

void setup()
{
  Serial.begin(9600);
  cell.begin(9600);
  
  Serial.print("Starting modem communication...");
  delay(12000);
  Serial.print("OK\nIntroduce your AT commands:\n"); 
}

void loop()
{
  if(cell.available() > 0)
  {
    incoming_char=cell.read();
    if((incoming_char >= ' ') && (incoming_char <= 'z'))
      Serial.print(incoming_char);
    else
    {
      Serial.print("%");
      Serial.print((int)incoming_char);
      Serial.print("%");
      if(incoming_char==10)
        Serial.println();
    }
  }

  if(Serial.available() > 0)
  {
    incoming_char = Serial.read();
    cell.print(incoming_char);
  }
}

The AT commands for receiving SMS are:

ATE1 --> Set echo ON
AT+CMGF=1 --> Establishes text mode in modem
AT+CMGL="REC UNREAD",1 --> Checks if exists unread SMS. Return OK if not exist any SMS, in other case returns a list with them (the first number of each of them are the index of each of them).
AT+CMGR=[sms_index],0 --> Read SMS with index sms_index from modem memory (ej: AT+CMGR=1,0).
AT+CMGD=[sms_index] --> Delete SMS with index sms_index from modem memory (ej: AT+CMGD=1).

The problem can be attached with your local operator. Are you using the SIM that came with the shield?.