Pasted

 
void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
Serial1.begin(57600);
}
 
void loop() {
  // put your main code here, to run repeatedly:                             
               
     Serial1.println("TEST INVIO");
     Serial1.flush();    
     Serial.println("Invio effettuato");  
     delay(1000);  
 
}