Query regarding call generated by sim900

Projects Networking, Protocols, and Devices
3

I am using serial communication between arduino and sim900.
code is:

SoftwareSerial mySerial(7, 8); 
void setup()
{
  mySerial.begin(19200);               // the GPRS baud rate   
  delay(500);
}
 
void loop()
{  
         DialVoiceCall();
}
 
void DialVoiceCall()
{
  mySerial.println("ATD + +xxxxxxxxxx;");//dial the number
  delay(100);
  mySerial.println();
}

now two Q's
1.How to collect response from sim900 corresponding to AT command for call generation
2.AT command to call no. from sim card is ATD>. But how to use it.