https://hungwenlin.com/blog/2010/%e5%bc%b7%e6%89%93%e8%98%8b%e6%9e%9c-iphone-%e6%a8%82-phone-%e5%b9%b4%e9%8a%b7%e7%99%be%e8%90%ac%e5%8f%b0-%e8%81%af%e6%83%b3%e6%8e%80%e8%b5%b7%e4%b8%ad%e5%9c%8b-3g-%e6%89%8b%e6%a9%9f%e6%96%b0%e6%88%b0/