Main article: History of mobile phones
An evolution of mobile phones
Radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s.
The first mobile telephone call made from a car occurred in St. Louis, Missouri, USA on June 17, 1946, using the Bell System's Mobile Telephone Service. The equipment weighed 80 pounds (36 kg), and the AT&T service, basically a massive party line, cost US$30 per month (equal to $337.33 today) plus 30–40 cents per local call, equal to $3.37 to $4.5 today.[5]
In 1956, the world’s first partly automatic car phone system, Mobile System A (MTA), was launched in Sweden. MTA phones were composed of vacuum tubes and relays, and had a weight of 40 kg. In 1962, a more modern version called Mobile System B (MTB) was launched, which was a push-button telephone, and which used transistors to enhance the telephone’s calling capacity and improve its operational reliability, thereby reducing the weight of the apparatus to 10 kg. In 1971, the MTD version was launched, opening for several different brands of equipment and gaining commercial success.[6][7]
Martin Cooper, a Motorola researcher and executive is considered to be the inventor of the first practical mobile phone for handheld use in a non-vehicle setting, after a long race against Bell Labs for the first portable mobile phone. Using a modern, if somewhat heavy portable handset, Cooper made the first call on a handheld mobile phone on April 3, 1973 to his rival, Dr. Joel S. Engel of Bell Labs.[8]
The first commercially automated cellular network (the 1G) was launched in Japan by NTT in 1979, initially in the metropolitan area of Tokyo. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nationwide 1G network. In 1981, this was followed by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and Sweden.[9] NMT was the first mobile phone network featuring international roaming. The first 1G network launched in the USA was Chicago-based Ameritech in 1983 using the Motorola DynaTAC mobile phone. Several countries then followed in the early-to-mid 1980s including the UK, Mexico and Canada.
The first "modern" network technology on digital 2G (second generation) cellular technology was launched by Radiolinja (now part of Elisa Group) in 1991 in Finland on the GSM standard, which also marked the introduction of competition in mobile telecoms when Radiolinja challenged incumbent Telecom Finland (now part of TeliaSonera) who ran a 1G NMT network.
In 2001, the launch of 3G (Third Generation) was again in Japan by NTT DoCoMo on the WCDMA standard.[10]
One of the newest 3G technologies to be implemented is High-Speed Downlink Packet Access (HSDPA). It is an enhanced 3G (third generation) mobile telephony communications protocol in the high-speed packet access (HSPA) family, also coined 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) to have higher data transfer speeds and capacity.
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Sabtu, 22 Oktober 2011
Rabu, 19 Oktober 2011
History
Most young humans have been observed to play with whatever they can find, turning such things as pinecones, rocks and food into toys. Toys and games have been unearthed from the sites of ancient civilizations. They have been written about in some of our oldest literature. Toys excavated from the Indus valley civilization (3000-1500 BCE) include small carts, whistles shaped like birds, and toy monkeys which could slide down a string.[2]
The earliest toys were made from materials found in nature, such as rocks, sticks, and clay. Thousands of years ago, Egyptian children played with dolls that had wigs and movable limbs which were made from stone, pottery, and wood.[3] In Ancient Greece and Ancient Rome, children played with dolls made of wax or terracotta, sticks, bows and arrows, and yo-yos. When Greek children, especially girls, came of age it was customary for them to sacrifice the toys of their childhood to the gods. On the eve of their wedding, young girls around fourteen would offer their dolls in a temple as a rite of passage into adulthood.[4][5]
A display of Roman toys, including several that would be familiar to children today: a doll, dice, rattles, and toy dishes for playing house
As technology changed and civilization progressed, toys also changed. Whereas ancient toys were made from materials found in nature like stone, wood, and grass modern toys are often made from plastic, cloth, and synthetic materials. Ancient toys were often made by the parents and family of the children who used them, or by the children themselves. Modern toys, in contrast, are often mass-produced and sold in stores.
This change in the nature of toys is exemplified by the changes that have taken place in one of the oldest and most universal of human toys; dolls. The earliest and most primitive dolls were simple wooden carvings and bundles of grass. Egyptian dolls were sometimes jointed so that their limbs could move realistically. By the early 19th century there were dolls that could say "mama".[6] Today there are computerized dolls that can recognize and identify objects, the voice of their owner, and choose among hundreds of pre-programmed phrases with which to respond.[7] The materials that toys are made from have changed, what toys can do has changed, but the fact that children play with toys has not changed.
The earliest toys were made from materials found in nature, such as rocks, sticks, and clay. Thousands of years ago, Egyptian children played with dolls that had wigs and movable limbs which were made from stone, pottery, and wood.[3] In Ancient Greece and Ancient Rome, children played with dolls made of wax or terracotta, sticks, bows and arrows, and yo-yos. When Greek children, especially girls, came of age it was customary for them to sacrifice the toys of their childhood to the gods. On the eve of their wedding, young girls around fourteen would offer their dolls in a temple as a rite of passage into adulthood.[4][5]
A display of Roman toys, including several that would be familiar to children today: a doll, dice, rattles, and toy dishes for playing house
As technology changed and civilization progressed, toys also changed. Whereas ancient toys were made from materials found in nature like stone, wood, and grass modern toys are often made from plastic, cloth, and synthetic materials. Ancient toys were often made by the parents and family of the children who used them, or by the children themselves. Modern toys, in contrast, are often mass-produced and sold in stores.
This change in the nature of toys is exemplified by the changes that have taken place in one of the oldest and most universal of human toys; dolls. The earliest and most primitive dolls were simple wooden carvings and bundles of grass. Egyptian dolls were sometimes jointed so that their limbs could move realistically. By the early 19th century there were dolls that could say "mama".[6] Today there are computerized dolls that can recognize and identify objects, the voice of their owner, and choose among hundreds of pre-programmed phrases with which to respond.[7] The materials that toys are made from have changed, what toys can do has changed, but the fact that children play with toys has not changed.
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