A cell phone, also known as a mobile phone, is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area. The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN). Most modern mobile phones have additional features beyond voice calling, such as SMS for text messaging, MMS for sending and receiving multimedia messages, internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones offering only those capabilities are referred to as feature phones; mobile phones which offer greatly advanced computing capabilities are referred to as smartphones.
The first commercially available device that could be properly referred to as a “smartphone” began as an experiment in 1992 by British telecommunications company BT Group plc (then known as British Telecom). In 2001, the Japanese firm NTT DoCoMo released the first smartphones to achieve mass adoption within a country. Smartphones became widespread in developed countries during the late 2000s.
Early history (before 1980)
Before cellular telephony was introduced, there were some attempts at using other forms of mobile radio for telephony outside of vehicles including hand-held two-way radios (walkie-talkies), Citizens’ Band (“CB”) radios and Railway Radios. These systems generally required at least two units per call: one carried by each party. They were unable to transmit voice clearly beyond about one mile (1.6 km). An approach used since 1978 has been placement of base stations far apart so their coverage areas overlap slightly; calls are then handed off from one base station’s territory into another’s automatically during travel between them. This system was originally conceived in 1947 by Douglas Harington Ring and Wartime Laboratories research group during World War II. Cellular telephony was first proposed in 1923 by Swedish engineer Lars Magnus Ericsson working forTelefonaktiebolaget LM Ericsson.:17 Bell Labs won US$33 million dollars funding from AT&T Corporation on October 26th 1946 which resulted in four researchers joining Bell Labs; John R. Pierce being one of these four.:220 Although it is often said that Halsall invented cellular telephony independently around this time,, no records show he filed any relevant patents or pursued commercial development of his ideas nor had any association with Bell Labs prior until after Pierce’s work had already begun.:221–222″