user3892: I tried the code shown below (found here)
void setup()
{
  Serial.begin(9600);  //Baud rate of the GSM/GPRS Module 
  Serial.print("\r");
  delay(1000);                  
  Serial.print("AT+CMGF=1\r");    
  delay(1000);
  Serial.print("AT+CMGS=\"+919449835011\"\r");    //Number to which you want to send the sms
  delay(1000);
  Serial.print("Test SMS -Jay\r");   //The text of the message to be sent
  delay(1000);
  Serial.write(0x1A);
  delay(1000); 
}
void loop()
{
}

I interfaced my GSM SIM900A module to the Arduino UNO (connections - GSM Tx to Arduino Rx, GSM Rx to Arduino Tx, GSM provided with supply (12V) using external adapter, GSM gnd to Arduino gnd).
I dumped the code into Arduino and then opened the Arduino IDE serial terminal. In the serial terminal, I get AT+CMGF=1AT+CMGS="+919449835011"Test SMS -Jay\r being displayed and I am not receiving any sms to my phone. I am not sure if its a problem with the code or connections.

user497: looks like you should be using Serial.begin(2400);
also, I'm assuming your sms phone number isn't actually 919449835011 and that that's not actually the number you used in your code

3892: <p>I tried the code shown below (<a href="http://letsplaywitharduino.blogspot.in/p/gsm-modem-with-arduino-uno.html" rel="nofollow">found here</a>)</p>

<pre><code>void setup()
{
  Serial.begin(9600);  //Baud rate of the GSM/GPRS Module 
  Serial.print("\r");
  delay(1000);                  
  Serial.print("AT+CMGF=1\r");    
  delay(1000);
  Serial.print("AT+CMGS=\"+919449835011\"\r");    //Number to which you want to send the sms
  delay(1000);
  Serial.print("Test SMS -Jay\r");   //The text of the message to be sent
  delay(1000);
  Serial.write(0x1A);
  delay(1000); 
}
void loop()
{
}
</code></pre>

<p>I interfaced my GSM SIM900A module to the Arduino UNO (connections - GSM Tx to Arduino Rx, GSM Rx to Arduino Tx, GSM provided with supply (12V) using external adapter, GSM gnd to Arduino gnd).</p>

<p>I dumped the code into Arduino and then opened the Arduino IDE serial terminal. In the serial terminal, I get <code>AT+CMGF=1AT+CMGS="+919449835011"Test SMS -Jay\r</code> being displayed and I am not receiving any sms to my phone. I am not sure if its a problem with the code or connections.</p>
 497: <p>looks like you should be using <code>Serial.begin(2400);</code></p>

<p>also, I'm assuming your sms phone number isn't actually 919449835011 and that that's not actually the number you used in your code</p>
