cellphone

(CELLular telePHONE) The first ubiquitous wireless telephone. Originally analog, all new cellular systems are digital, which has enabled the cellphone to turn into a smartphone that has access to the Internet. Digital cellphone systems are also offered in the PCS band, which is radio spectrum that was auctioned off by the U.S. government in the mid-1990s. Introduced in the mid-1980s, cellphone sales exploded worldwide in the 1990s. By 2008, there were more than three billion cellphones in use. Outside the U.S., cellphones are also called "mobile phones" or "mobiles."

Major Carriers
In the U.S., the major cellular carriers are AT&T (formerly Cingular), Verizon Wireless (formerly Bell Atlantic Mobile), Sprint Nextel (merger of Sprint and Nextel), T-Mobile, Alltel and Virgin Mobile USA. The largest cellular company in the world is UK-based Vodafone, which includes substantial ownership in Verizon Wireless.

Cell Technology
Geographic areas are divided into a number of slightly overlapping circular "cells." Each cell contains a base station, which is identifiable by its transmitting and receiving antenna located on a tower at the top of a hill or building. The base stations connect to the landline telephone system of the country.

The multiple cells combined with low power transmitters allow the same frequencies to be reused with different conversations in different cells within the same city or locale. The primary digital cellphone technologies are TDMA, CDMA and GSM. See 3G, AMPS, GSM, TDMA, CDMA, WAP, cellspace, smartphone, screaming cellphone and cordless phone.

The Cells

The cellular system uses multiple base stations to cover a geographic area. As the mobile phone user travels from cell to cell, the call is automatically "handed off" to the next station. The more cells, the more customers can be handled in the entire system overall, because the same frequencies can be reused within the cell.

First Cellphone in U.S.

Introduced in 1983, this Motorola DynaTAC cost $3,995 and weighed two pounds. (Image courtesy of Motorola, Inc.)

Could They Have Imagined?

As Europeans began to use their new-fangled Ericsson phones in the late 1800s, could they have imagined the wireless world 100 years later? Picture taken at Antoni Gaudi's famous "La Pedrera" apartment house in Barcelona.