iPhone is a Smartphone designed and marketed by Apple Inc. The first generation of iPhone was unveiled on January 9, 2007 by Apple president Steve Jobs, although official sales started on June 29, 2007. The first generation of iPhone was 2G but later it upgraded to 3G from the 2nd and onward versions. All the versions are powered by the iOS, a specialized mobile Operating System made exclusively for iPhone by Apple.

iPhone has a 3.5 inch scratch-proof capacitive touch screen. Majority of user inputs are done by this touch screen and hardware inputs are limited by just 4 buttons. It has proximity sensor to detect the phone position and an accelerometer to detect phone rotation. First generation of iPhone lacks the GPS feature although later A-GPS is added into iPhone.

iPhone provides Bluetooth 2.x+EDR connectivity for wireless headphone and other accessories but it does not allow users to share Multimedia files over Bluetooth. For better music experience iPhone has a standard 3.5 mm audio jack connector.

According to official specifications, first generation of iPhone battery was capable of supporting 250 hours standby, 8 hours of talk time and 24 hours music playing while the latest version of iPhone, iPhone 4 offers 300 hours standby, 24 hours music, 12 hours 2G and 5 hours 3G talk time.

First two versions of iPhone have a 2 MP fixed focus camera. 3GS has a 3.2 MP camera and iPhone 4 has a 5 MP video recording enabled camera. The camera on iPhone 4 has an LED flash, High ISO sensitivity and HD quality video recording capabilities.

iPhone does not support external storage card. It features very large internal storage, it has many variant ranging from 4GB to 32GB storage.

To provide the best possible flexibility, iPhone interface and software are specially designed for the iPhone OS. iPhone supplies a lot of bundled software like digital compass, Map, Calculator, Web browser, Mail client, Organizer and many more. It also supports 3rd party software. It has direct integration with Apple stores and multimedia sharing and social networking sites.

As a phone iPhone has all the basic features like conference call, caller holding, caller id and other network services. First generation of iPhone only supports 2G but later version includes a faster data transfer speed. iPhone 3G has UMTS and HSDPA 3.6 mbps connectivity but iPhone 3GS supports HSDPA 7.2 mbps connectivity.

The Apple iPhone is a revolutionary phone in mobile phone industry. It has made a drastic change in user interface and mobile phone user performance all over the mobile world.