#include <SoftwareSerial.h>
SoftwareSerial mySerial(5, 4); // RX, TX

void setup() {
  Serial.begin(38400);
  while (!Serial) { }
  Serial.println("Serial");
  mySerial.begin(38400);
  mySerial.println("Soft serial");
}

void loop() {
  if (mySerial.available()) {
  Serial.write(mySerial.read());
  }

  if (Serial.available()) {
  mySerial.write(Serial.read());
  }
}