When cartoonist Chester Gould gave comic detective Dick Tracy a two-way wrist radio, he could not have known he was anticipating the development of a variety of portable communications devices. The digital revolution of the late twentieth century led to communication devices that make Tracy's wrist radio look quaint.
CELLPHONES
In 1979, the world's first wireless network was launched online in Tokyo, Japan. Similar networks quickly spread after that, and by 2006, most people in North America, Europe, and affluent areas of Africa, Asia, and Latin America had access to cell phones. It is reported that 206 million people use cell phones in the United States, as of 2011.
SMARTPHONES
A smart phone is a small computer that also doubles as a phone. Although features vary by manufacturer and model, smartphones typically include digital voice service, Internet access, email and text messaging. Other options include MP3 players, digital cameras and video players. Smartphones also have a wide range of computer applications for business and entertainment. Major brands of smartphones include BlackBerry, iPhone, Motorola and Samsung.
LAPTOP COMPUTERS
A laptop computer is a mobile computer. When they were introduced for the first time, they were little better than glorified calculators. Today's high-end machines have the same functionality as desktop computers, including Internet access that allows the use of various communication tools such as instant messaging, e-mail and video conferencing. The most popular models are manufactured by Dell, Apple, Gateway and Toshiba.
DIGITAL PERSONAL ASSISTANT
Personal digital assistants, or PDAs, have evolved considerably since their introduction in 1993. Originally little more than electronic address books, PDAs are now multi-function portable computers. Features vary, but often include telephone service, fax service, email and Internet. Users control their PDAs by writing information about touchscreens, LCD or LCD, with stylus devices called stylus. Employers often equip employees with PDAs in situations where laptops would be unfeasible.