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Transcript of Mobile phone
or "cell phone") is a long-range, portable electronic device used for
mobile communiction. In addition to the standard voice function of a
telephone, current mobile phones can support many additional
services such as SMS for text mesasaging, email, packet switching for
access to the Internet, and MMS for sending and receiving photos and
video. Most current mobile phones connect to a cellular network of
base stations (cell sites), which is in turn interconnected to the public
switched telephone network (PSTN) (the exception are satellite phones).
History The introduction of hexagonal cells for mobile phone base stations, invented in 1947 by Bell Labs engineers at AT&T, was further developed by Bell Labs during the 1960s. Radiophones have a long and varied history going back to the Second World War with military use of radio telephony links and civil services in the 1950s, while hand-held cellular radio devices have been available since 1983. Due to their low establishment costs and rapid deployment, mobile phone networks have since spread rapidly throughout the world, outstripping the growth of fixed telephony.
In 1945, the 0G generation of mobile telephones were introduced. 0G mobile telephones, such as Mobile Telephone Service, were not officially categorized as mobile phones, since they did not support the automatic change of channel frequency in the middle of a call, when the user moved from one cell (base station coverage area) to another cell, a feature called "handover".
In 1970 Amos Joel of Bell Labs invented the "call handoff" feature, which allowed a mobile-phone user to travel through several cells during the same conversation. Martin Cooper of Motorola is widely considered to be the inventor of the first practical mobile phone for handheld use in a non-vehicle setting. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a handheld mobile phone on April 3, 1973. At the time he made his call, Cooper was working as Motorola's General Manager of its Communications Division.
Fully automatic cellular networks were first introduced in the early to mid-1980s (the 1G generation). The first fully automatic mobile phone system was the 1981 Nordic Mobile Telephone (NMT) system. Until the early 1990s, most mobile phones were too large to be carried in a jacket pocket, so they were usually permanently installed in vehicles as car phones. With the advance of miniaturization and smaller digital components, mobile phones got smaller and lighter.