Interesting Facts About Mobile Phones
by: Roberto Sedycias
Mobile phone (telefone celular) is a wireless, portable,
long-range, electronic telephone, which during travel can
seamlessly change antenna connections, from one radio reception
cell to another radio reception cell, without dropping or losing
the ongoing call.
Besides the standard voice function of a telephone, latest
Mobile phones (telefone celular) have features such as SMS for
text messages, MMS for multimedia messages, radio, games,
internet connectivity for email, browsing, blogging, music (MP3)
playback, memo recording, built-in cameras and camcorders,
ringtones, personal organizers, Push-to-Talk (PTT), Bluetooth
and infrared connectivity, call registers, streaming video,
downloading video, video call, and also serve as wireless modems
for PCs that can be connected to the Internet.
The power in a mobile phone (telefone celular) is obtained from
rechargeable batteries, which can be recharged from the mains, a
USB port or a cigarette lighter port in an automobile. Nickel
Metal Hydride were the most common types of batteries, which due
to the "memory effect" (the user can recharge only when the
entire battery is drained off) were replaced by Lithium-Ion
batteries, which did not suffer from any memory effect.
Mobile phones (telefone celular) came into existence because of
the invention of hexagonal cells in 1947, for the base stations
by Bell Labs engineers at AT&T. This was further developed
during the 1960s by Bell Labs. During a call, the channel
frequency could not be changed automatically from one cell (base
station coverage area) to another cell (base station coverage
area) as the person traveled from the area of one cell to the
area of another cell. Amos Joel of Bell Labs invented a
breakthrough invention and called it as the `call handoff` by
which the channel frequency could be changed automatically from
one cell to another cell, during the same call, as the mobile
user traveled from one cell to another cell. Due to their heavy
construction, these phones were used mainly in automobiles.
The first practical mobile phone in a non-vehicle setting, and
which could be handheld, was invented by Martin Cooper, the
General Manager (Communications Division) of Motorola, who made
the world`s first handheld mobile phone (telefone celular) call
on April 3, 1973.
The technology by which the mobile phone (telefone celular)
works depends on the mobile phone operator; however, all of them
use electromagnetic radio waves, which are in touch with a cell
site (base station). The base station is composed of several
antennas which are mounted on a pole, tower, or building. Cell
sites are spread at a distance of 5 to 8 miles (approx. 8 to 13
km) from each other. The low power transceiver from the mobile
phone transmits the voice and data to the nearest cell site.
During movement, the mobile phone will "handoff" the information
to other cell site. Mobile phone operators use many technologies
to maintain the smooth stream of digitized data from the mobile
phone to the cell site and vice versa.
The wireless telephone technologies are grouped under heads
known as generations, starting from zero generation or 0G. The
current generation going on is 4G; however, there are old mobile
phones (telefone celular) that still operate on 1G, 2G, and 3G
technologies. The wireless telephone technologies used in each
generation are as given below:
0G: PTT, MTS, IMTS, AMTS, OLT, MTD, Autotel/PALM, ARP
1G: NMT, AMPS/TACS/ETACS, Hicap, CDPD, Mobitex, DataTac
2G: GSM, iDEN, D-AMPS, IS-95/cdmaOne, PDC, CSD, PHS, GPRS, HSCSD,
WiDEN, CDMA2000 1xRTT/IS-2000, EDGE (EGPRS)
3G: W-CDMA, UMTS (3GSM), FOMA, TD-CDMA/UMTS-TDD, 1xEV-DO/IS-856,
TD-SCDMA, GAN (UMA), HSPA, HSDPA, HSUPA, HSPA+, HSOPA
4G : UMB, UMTS Revision 8 (LTE), WiMAX
Frequency bands: SMR, Cellular, PCS
The impact of mobile phone (telefone celular) usage on human
health has been of considerable worldwide concern. Research
studies in Copenhagen, from the Danish Institute of Cancer
Epidemiology, the National Cancer Institute, and the Institute
of Cancer Research, do not establish any link between cancer and
mobile phone usage. However, an intergovernmental agency IARC
(International Agency for Research on Cancer) forming part of
the World Health Organization of the United Nations, undertook a
study of 4,500 users and found a statistically significant link
between mobile phone usage and tumor frequency. Further research
is going on.
Mobile phone (telefone celular) usage and driving is a common
worldwide phenomenon. Some jurisdictions have banned usage of
hand-held phones during driving, but allowed the hands-free
fashion of mobile phone usage while driving. However, studies
have found out that the distraction is caused by the
conversation itself; hence, both hand-held and hands-free mobile
phones contribute towards road traffic accidents. Further
studies on mobile phone usage and driving are going on.
Nokia Corporation is currently the world`s largest manufacturer
of mobile phones (telefone celular). Other notable mobile phone
manufacturers, in alphabetical order, are 3G, Audiovox (now UT
Starcom), Benefon, BenQ-Siemens, Fujitsu, High Tech Computer
Corporation (HTC), Kyocera, LG Mobile, Motorola, NEC, Panasonic
(Matsushita Electric), Pantech Curitel, Philips, Research In
Motion, Sagem, Samsung, Sanyo, Sharp, Siemens, Sierra Wireless,
SK Teletech, Sony Ericsson, T&A Alcatel, Toshiba, and Verizon.
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