The iPhone ( /ˈaɪfoʊn/ EYE-fohn) is a line of smartphones designed and marketed by Apple Inc. The iPhone runs Apple’s iOS mobile operating system, originally named iPhone OS. The first iPhone was released in 2007; the most recent iPhone, the 6th-generation iPhone 5, was released on September 21, 2012. The user interface is built around the device’s multi-touch screen, including a virtual keyboard rather than a physical one. The iPhone has Wi-Fi and cellular connectivity (2G, 3G and 4G (iPhone 5 only)).
An iPhone can shoot video (though this was not a standard feature until the iPhone 3GS), take photos, play music, send and receive email, browse the web, send texts, and receive visual voicemail. Other functions — games, reference, GPS navigation, social networking, etc. — can be enabled by downloading apps; as of 2012, the App Store offered more than 700,000 apps by Apple and third parties.
There are six generations of iPhone models, each accompanied by one of the six major releases of…