https://purengom.com/2010/07/14/iphone%ec%9d%b4-%ec%a0%84%ed%99%94%ea%b8%b0%ea%b0%80-%eb%90%98%eb%a9%b4%ec%84%9c-%ec%a2%8b%ec%95%84%ec%a7%84-%ec%a0%90%ec%9d%80/