There are 5 generations of iPhone models, the iPhone, iPhone 3G, iPhone 3GS, iPhone 4 and iPhone 4S, each with a similar design, and accompanied by one of the 5 major releases of the iPhone Operating System. All iPhone smartphones are designed by Apple Inc.

The original iPhone that was unveiled by Steve Jobs in January 2007 was a GSM phone which established the design precedents of the screen size and button placement which stayed through all the iPhone models. The first advertisement for the iPhone, titled “Hello,” aired during the 79th Academy Awards in 2007. The advert features clips from several notable films and television shows over the last 70 years with all characters answering telephones and saying “hello”. The iPhone is shown at the end with the caption “Hello. Coming in June.”

The iPhone 3GS added a compass, faster processor, and higher resolution camera, including video recording at 480p. The iPhone 4 that was released in June 2010 offered a rear-and-front facing camera for FaceTime video calling and for use in other apps like Skype. The iPhone 4 also featured a higher-resolution 960 × 640 display. The 5th generation iPhone, the iPhone 4S was released in October 2011 and added a 8 megapixel camera with 1080p video recording, face detection, and video stabilization, a faster dual core processor, support for both GSM/UMTS and CDMA on one chip, GLONASS support and a natural language voice control system called Siri.

An iPhone can function as a video camera, a camera phone, a portable media player, can send texts messages, receive visual voice mail, has both Wi-Fi and 3G connectivity and offer email and web browsing capabilities. The user interface is built around the device’s touch screen facility that includes an on screen keyboard. The App Store function on the iPhone offer downloadable software that include games, GPS navigation, social networking, security, television shows and films.