મંગળવાર, 8 માર્ચ, 2011

History Of Mobile Phones

History Of Mobile Phones



History Of Mobile Phones
This history of mobile phones chronicles the development of handheld radio telephone technology from two-way radios in vehicles to handheld cellular phones.
In the beginning, two-way radios (known as mobile rigs) were used in vehicles such as taxicabs, police cruisers, ambulances, and the like, but were not mobile phones because they were not normally connected to the telephone network. Users could not dial phone numbers from their mobile radios in their vehicles. A large community of mobile radio users, known as the mobileers, popularized the technology that would eventually give way to the mobile phone. Originally, mobile phones were permanently installed in vehicles, but later versions such as the so-called transportables or "bag phones" were equipped with a cigarette lighter plug so that they could also be carried, and thus could be used as either mobile or as portable two-way radios. During the early 1940s, Motorola developed a backpacked two-way radio, the Walkie-Talkie and later developed a large hand-held two-way radio for the US military. This battery powered "Handie-Talkie" (HT) was about the size of a man's forearm.
First generation
The first commercial launch of cellular telecoms was launched by NET in Tokyo Japan in 1979. In 1981 the NMT system was launched in Denmark, Finland, Norway and Sweden. The first handheld mobile phone in the US market was the Motorola_Dyna 8000X, which received approval in 1983. Mobile phones began to proliferate through the 1980s with the introduction of "cellular" phones based on cellular networks with multiple base stations located relatively close to each other, and protocols for the automated "handover" between two cells when a phone moved from one cell to the other. At this time analog transmission was in use in all systems. Mobile phones were somewhat larger than current ones, and at first, all were designed for permanent installation in vehicles (hence the term car phone). Soon, some of these bulky units were converted for use as "transportable" phones the size of a briefcase. Motorola introduced the first truly portable, hand held phone. These systems (NIT, AMPS, SACS, RT MI, C-Net, and Radio com 2000) later
Second generation

A 1991 GSM mobile phone
In the 1990s, 'second generation' (2G) mobile phone systems such as GSM, IS-136 ("TDMA"), iDEN and IS-95 ("CDMA") began to be introduced. In 1991 the first GSM network (Radiolinja) opened in Finland. 2G phone systems were characterized by digital circuit switched transmission and the introduction of advanced and fast phone to network signaling. In general the frequencies used by 2G systems in Europe were higher though with some overlap, for example the 900 MHz frequency range was used for both 1G and 2G systems in Europe and so such 1G systems were rapidly closed down to make space for 2G systems. In America the IS-54 standard was deployed in the same band as AMPS and displaced some of the existing analog channels.
Coinciding with the introduction of 2G systems was a trend away from the larger "brickle" phones toward tiny 100–200g hand-held devices, which soon became the norm. This change was possible through technological improvements such as more advanced batteries and more energy-efficient electronics, but also was largely related to the higher density of cellular sites caused by increasing usage levels which decreased the demand for high transmit powers to reach distant towers for customers to be satisfied.
The second generation introduced a new variant to communication, as SMS text messaging became possible, initially on GSM networks and eventually on all digital networks. The first machine-generated SMS message was sent in the UK in 1991. The first person-to-person SMS text message was sent in Finland in 1993. Soon SMS became the communication method of preference for the youth. Today in many advanced markets the general public prefers sending text messages to placing voice calls.
2G also introduced the ability to consume media content on mobile phones, when Radiolinja (now Elisa) in Finland introduced the downloadable ringing tone as paid content. Finland was also the first country where advertising appeared on the mobile phone when a free daily news headline service on SMS text messaging was launched in 2000, sponsored by advertising.
became known as first generation (1G) mobile phones.

1 ટિપ્પણી(ઓ):

Unknown કહ્યું...

It is very amusing to see the communication technology's progress. Way back, companies only rely on a 1800 Number for communication purposes. Nowadays, we also have mobile phones that can help us with our livelihood.

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