Software Serial Research and Questions

In serialEvent() add digitalWrite(13, HIGH); then type in the serial monitor and let me know is the LED comes on.

The LED (L) has turned ON!

void setup() 
{
  Serial.begin(9600);
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW);
}

void loop() 
{
  for (int i=0; i<5; i++ )
  {
   ;
  }
}

void serialEvent()
{
  digitalWrite(13, HIGH);
  byte x = Serial.read();
  Serial.write(x);
}