Balancing Robot Bluetooth Configuration

void setup() {

  Serial.begin(9600);

  Serial.println("Enter AT commands:");

  Serial1.begin(9600);

}

void loop() {

  char c=' ';

  if (Serial1.available())

    Serial.write(Serial1.read());   

  if (Serial.available()){

    c=Serial.read();

    Serial1.write(c);

    Serial.write(c);

  }

}