UartClient.ino

#include <SoftwareSerial.h>

// Not all pins on the Leonardo support change interrupts, 
// so only the following can be used for RX: 
// 8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).
SoftwareSerial mySerial(14, 15); // RX, TX

void setup()
{
  // Open serial communications and wait for port to open:
  Serial.begin(57600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  Serial.println("Goodnight moon!");

  // set the data rate for the SoftwareSerial port
  mySerial.begin(9600);
  mySerial.println("Hello, world?");
}

void loop() // run over and over
{
    while (mySerial.available()) {
        int in = mySerial.read();
        // Serial.print(in);
        mySerial.write(in);
    }
}