#define SERIAL_CLIENT1  1
#define SERIAL_CLIENT2  2
#define LED 10

void setup() {
   pinMode(LED, OUTPUT);
   Serial.begin(9600);
   delay(1000);
}

void loop() {

  Serial.write(SERIAL_CLIENT1);
  Serial.write(0x01);
  delay(1000);
 
  Serial.write(SERIAL_CLIENT1);
  Serial.write(0x00);
  delay(1000);
  
  Serial.write(SERIAL_CLIENT2);
  Serial.write(0x01);
  delay(1000);
 
  Serial.write(SERIAL_CLIENT2);
  Serial.write(0x00);
  delay(1000);

  digitalWrite(LED,HIGH);
   delay(500);
   digitalWrite(LED,LOW);
   delay(100);

}