Arduino UNO + RN2483 needs power interrupt to start

sys set pindig GPIO0 1 to switch it on and sys set pindig GPIO0 0 to switch if off

To wake it from sleep I use ;

void wakeUP_RN2483() {
  Serial1.end();
  pinMode(PIN_SERIAL1_TX, OUTPUT);
  // Send a break to the RN2483
  digitalWrite(PIN_SERIAL1_TX, LOW);
  delay(5);  
  digitalWrite(PIN_SERIAL1_TX, HIGH);
  Serial1.begin(57600);
  // Send magic character for autobaud.
  Serial1.write(0x55);
}

Obviously to need to use the settings for the serial port it is attached to (which in my case is Serial1)