Since the creation of walkie-talkies in the 1940s, the development of mobile devices has a come a long way. Today mobiles are not solely used for telecommunications; they are also heavily used for computing. The various mobiles runs with an operating system designed to efficiently connect with wireless networks. Data are usually transmitted to mobiles with use of digital radio signal, GPS, Bluetooth and infrared. Mobile devices or handheld devices are portable, small and lightweight. Most devices weigh less than two pounds. They are typically designed with display screens and with miniature keyboards. They are heavily used in voice calls, text messaging, video conferencing, gaming and web browsing. Among the top mobile devices today are smartphones, tablets and e-book readers.

Smartphones

A smartphone uses a system that is a combination of mobile operating system and personal computer operating system. Although it has features of a personal computer, it is not considered as a replacement for desktop and laptop computers. The smartphone is designed with a touchscreen interface. Common screens used are either LED, LCD or AMOLED. A smartphone has combined features of mobile phones and other mobile devices like media player, PDA and GPS navigation units. It can also be used as a camera phone. It can run downloaded apps as well. Smartphones manufactured in 2012 are equipped with 4G or fourth generation cellular network technology for enhanced mobile telecommunication and faster internet connection.

Tablets

A tablet is considered as a mobile computer but it does not have the full functionality of a desktop or a laptop computer. It is designed with a touchscreen interface and a virtual keypad that pops up on the screen. Some tablets are called convertibles or hybrids; they have physical keyboards that can be detached or concealed. Most tablets have7 inches screens and they are a little bit larger than smartphones. Some types of tablets can also be used as phones and they are popularly known as phablets. They are also equipped with a camera, sensor and microphone. They may also have several ports for battery charging, Ethernet and other network connections. Other physical features include power buttons and speaker volume buttons.

E-book readers

An electronic e-book reader is portable electronic device that contains the digital form of a publication. It can contain not only text but also images. An e-book reader has a touchscreen interface that can be controlled for different viewing preferences. The idea of creating an e-book reader dates as far back as the 1930s when Bob Brown thought of a machine that would keep a wide selection of printed materials. It was in the 1990s that Sony launched an e-book reader that can read e-book on CDs. Today, e-book readers come in sizes much more similar to tablets. It could read e-books in various formats such as epub and pdf.