Arduino Serial Console (ASCII)

int ledPin = 13;

void setup(){
    //Startup serial at 9600 BAUD
  Serial.begin(9600);
    //Set pin 13 to OUTPUT
  pinMode(ledPin, OUTPUT);
}

void loop(){
    /* Read and report data from serial, while the serial console
     * is available, and set the LED on.
     *
     * If the serial console is not available, set the LED low and
     * wait for more input.
     */
  while(Serial.available() > 0){
    Serial.write(Serial.read());
    digitalWrite(ledPin, HIGH);
  } if(Serial.available() == 0){
    digitalWrite(ledPin, LOW);
  }
}