As the technology in telecommunication field is getting more sophisticated, people are getting easier in communicating. They can contact their relatives who live abroad by phone easily. If you often use the phone, you must feel the convenience that you get when calling your family or friends by phone. However, phone can also ruin your privacy. When you need to be alone, the unwanted calls sometimes keeps contacting you and you can’t focus to your job. To help you out of this situation, all you c...