int incomingByte = 0;

void setup() 
{
 Serial.begin(57600); //serial port to computer
 Serial1.begin(57600); //serial port to RN
 delay(1000);
}

void loop() {

  joinRequest();
   Serial.print("Join Request is : ");
   Serial.println(incomingByte);
   delay(5000);

  int ok=0;
  while ( ok == 0 ){
   
    if (Serial.available() > 0) {
    incomingByte = Serial.read();

    Serial.print("I received: ");
    Serial.println(incomingByte, DEC);
    ok=1;
  }
   }
  }

void joinRequest()
{

Serial1.write("mac join otaa\r\n");
delay(1000);
while(Serial1.available())
Serial.write(Serial1.read());
delay (3000);
}