Wireless was the original word for "radio." Essentially, it meant wireless telegraphy. The term was widely used in the early twentieth century but fell out of use in the United States and was almost entirely replaced by the word radio before World War II. But today the term wireless is back in a big way. It still means "radio," but it has some specific modern implications. Nowadays, wireless refers primarily to the enormous cellular telephone industry. After all, cell phones are basically sophisticated two-way radios.

With over 800 million cell phones sold in 2005, the cell phone is the largest-volume consumer electronics device. It has changed the way that we communicate. Also 2005 was the year in which cell phone subscribers numbered more than wired telephone subscribers. Furthermore, as the data speed of the newer digital cell phone transmissions increases, more cell phone applications are possible. These include cameras, Internet access, e-mails, audio, gaming, and video. This chapter provides a technical overview of cell phone standards and operation. Other short-range wireless technologies are covered in Chap. 21.