According to tech gurus, there are two basic differences between ordinary mobile phones and smartphones: the way they are built and the things they can do. They are built by making use of open systems to take advantage of the skills, energy and innovation of numerous companies from a vast range of industries. This means that smartphones extend the traditional track record of mobile phones by constant and rapid improvement.
Regarding their capabilities, a lot is expected from them: wireless e-mail, Internet, Web browsing, and fax, intercom function, personal information management, online banking, LAN connectivity, Graffiti style data entry, local data transfer between phone set and computers, remote data transfer between phone set and computers, remote control of computers and much more. The common traits that seem to be there in smartphones are that they should be voice-centric devices (voice is the primary function, data is secondary) and offer PDA-like capabilities.
The problem is that almost all the new mobile phones have some rudimentary PDA functionalities such as phonebooks, calendars, and to-do lists. Moreover, BREW and Java ME devices have capabilities for installation of additional applications; but these devices are not yet considered smartphones. In addition to that the constant additions in capabilities of all mobile phones, the qualifying features of smartphones are getting complicated. For the finale, it can said that so long your phone is capable of offering the best of what a mobile phone has to offer, it will be regarded as a smartphones.