Arduino interphone with RDA5807M & KT0803

Arduino walkie talkie /Arduino two way radio used RDA5807M & KT0803.
Please use IDE 1.5.7 to complete,or go worng.
pin 4 is indicate to transmit.

#include <Arduino.h>
#include <Wire.h>
#include <radio.h>
#include <RDA5807M.h>
#include <FMTX.h>

RDA5807M radio;         // Create an instance of Class for RDA5807M Chip
RADIO_INFO ri;          //rssi
float fm_freq = 108.0;  //tx freuqency
int i = 0;
int k = 0;
int ptt = 3;
void setup() {
  pinMode(ptt, INPUT);  //PTT
  pinMode(4, OUTPUT);
  i2c_init();
  radio.init();
  radio.setFrequency(10800);  //rx frequency
  radio.setVolume(5);         //set volume,max=15
  radio.setMono(false);
  radio.setMute(false);
  digitalWrite(4, LOW);
  i = 0;
}
void loop() {
  if (digitalRead(ptt) == HIGH) {
    radio.setMute(true);
    while (k == 0) {
      i2c_init();
      delay(200);
      fmtx_set_freq(fm_freq);
      digitalWrite(4, HIGH);
      k = 1;
    }
    i = 1;
  }
  delay(100);
  if (i == 1 && digitalRead(ptt) == LOW) {
    radio.setFrequency(10800);
    radio.setVolume(5);
    radio.setMono(false);
    radio.setMute(false);
    digitalWrite(4, LOW);
    k = i = 0;
  }
  radio.getRadioInfo(&ri);  //mute control
  if ((ri.rssi) >= 7) radio.setMute(false);
  else if ((ri.rssi) < 7) radio.setMute(true);
  delay(100);
}

Source here:http://www.crystalradio.cn/forum.php?mod=viewthread&tid=1690359&extra=page%3D1&mobile=2
I do as this.It's include FMTX libraly and schmatic.