A mobile phone (also known as a cellular phone, cell phone and a hand phone) is a device that can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network. By contrast, a cordless telephone is used only within the short range of a single, private base station.
In addition to telephony, modern mobile phones also support a wide variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones that offer these and more general computing capabilities are referred to as smartphones.
The first hand-held mobile phone was demonstrated by Dr Martin Cooper of Motorola in 1973, using a handset weighing around 1 kg. In 1983, the DynaTAC 8000x was the first to be commercially available. In the twenty years from 1990 to 2010, worldwide mobile phone subscriptions grew from 12.4 million to over 4.6 billion, penetrating the developing economies and reaching the bottom of the economic pyramid.
A tablet computer, or a tablet, is a mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen rather than using a physical keyboard. It often uses an onscreen virtual keyboard, a passive stylus pen, or a digital pen.
The term may also apply to a variety of form factors that differ in position of the screen with respect to a keyboard. The standard form is called slate, which does not have an integrated keyboard but may be connected to one with a wireless link or a USB port. Convertible notebook computers have an integrated keyboard that can be hidden by a swivel joint or slide joint, exposing only the screen for touch operation. Hybrids have a detachable keyboard so that the touch screen can be used as a stand-alone tablet. Booklets include two touch screens, and can be used as a notebook by displaying a virtual keyboard in one of them.
Early examples of the information tablet concept originated in the 19th and 20th centuries mainly as prototypes and concept ideas; prominently, Alan Kay's Dynabook. First commercial portable electronic devices based on the concept appeared at the end of the 20th century. During the 2000s Microsoft attempted a relatively unsuccessful product line with Microsoft Tablet PC, which carved a niche market at hospitals and outdoor businesses. In 2010 Apple released the iPad based on the technology developed in parallel with their previous iPhone, and reached worldwide commercial success.