"Smart phones differ from ordinary mobile phones in... how they are built and what they can do."
David Wood, Symbian
There is no standard definition for a smart phone, but in its basic sense it is a mobile phone with advanced functions. The first—called "Simon"—was developed by IBM in 1992 and released to the public in 1993. Simon's features included a calendar, an address book, a calculator, a notepad, e-mail, and fax capabilities. Instead of buttons for dialing, it had a touch screen for browsing and an on-screen keyboard for text input.
In 1996 Nokia released its first smart phone, which combined their best-selling phone with the successful, but very expensive, palmtop computer developed by Hewlett-Packard. Later, several operating systems were developed specifically for smart phones, now a requirement for some smart phone definitions.
The most widely used smart phone operating System is Symbian, which in 2005 accounted for 56 to 85 percent (depending on the definition used) of the market. Smartphone applications expanded to include cameras, music players, and accelerators to allow the use of business documents such as PDFs and MS Office documents. Internet browsers, Wi-Fi, and the global positioning system (GPS). With Wi-Fi comes the possibility of using Voice over Internet Protocol (VolP) to make phone calls over the Internet. It is possible that in the future the phone component of the mobile phone will be dropped altogether and the smart phone will simply be a computer.