The iPhone (pronounced /ˈaɪ.foʊn/ EYE-fohn) is a line of Internet and multimedia-enabled smartphones designed and marketed by Apple Inc. The first iPhone was introduced on January 9, 2007.
The iPhone allows audio conferencing, call holding, call merging, caller ID, and integration with other cellular network features and iPhone functions. For example, if music is playing when a call is received, the music fades out, and fades back in when the call has ended. The proximity sensor shuts off the screen and touch-sensitive circuitry when the iPhone is brought close to the face, both to save battery and prevent unintentional touches. The iPhone does not support video calling or videoconferencing on versions prior to the 4th generation, as there is only one camera on the opposite side of the screen. The iPhone 4 supports video calling using either the front or back camera over wi-fi, a feature Apple calls "Facetime". The first two models only support voice dialing through third party applications. Voice control, available only on the iPhone 3GS, allows users to say a contact's name or number and the iPhone will dial.