arduino uno + sim900 linkspirit

#include <SoftwareSerial.h>
SoftwareSerial SIM900(7, 8); 
void setup()
{
  SIM900.begin(19200);
  SIM900power();
  delay(20000);  
}

void SIM900power()

{
  digitalWrite(9, HIGH);
  delay(1000);
  digitalWrite(9, LOW);
  delay(5000);
}
 void reciveVoiceCall()
 {
 SIM900.println(“ATS0=3”);
   delay(100);
  SIM900.println();
  delay(300000);            
  SIM900.println(“ATH”);   
 }
 
void loop()
{
   if(SIM900.available() >0)
   {
  reciveVoiceCall();
   }
}

i want to make simple program for reciving a phone call automatically .the above code is not working can any one tell me the right syntax of writing at command ats0

Replace the two lines of your code with the following:

 SIM900.println("ATS0=3");
SIM900.println("ATH");

You are using the wrong quotation marks.