GSM Module Sim900A

#include <SoftwareSerial.h>

SoftwareSerial SIM900A(10,11);

void setup()
{
  SIM900A.begin(9600);   //  the baud rate of GSM Module  
  Serial.begin(9600);    // the baud rate of Serial Monitor (Arduino)
  Serial.println ("SIM900A Ready");
}


void loop()
{
  if (Serial.available()>0)
   switch(Serial.read())
  {
    case 's':
      SendMessage();
      break;
  }

 if (SIM900A.available()>0)
   Serial.write(SIM900A.read());
}


 void SendMessage()
{
  Serial.println ("Sending Message");
  SIM900A.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);
  Serial.println ("Set SMS Number");
  SIM900A.println("AT+CMGS=\"+959441803792 \"\r"); //Mobile phone number to send message
  delay(1000);
  Serial.println ("Set SMS Content");
  SIM900A.println("Good morning, how are you doing?");// Messsage content
  delay(100);
  Serial.println ("Finish");
  SIM900A.println((char)26);// ASCII code of CTRL+Z

}