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New Zealand Phone Info
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Mobile phones and the network they
operate under vary significantly from provider to provider, and
even from nation to nation. However, all of them communicate
through electromagnetic radio waves with a cell site base
station, the antennas of which are usually mounted on a tower,
pole, or building.
The phones have a low-power transceiver that transmits voice and
data to the nearest cell sites, usually 5 to 8 miles
(approximately 8 to 13 kilometres) away. When the cellular phone
or data device is turned on, it registers with the mobile
telephone exchange, or switch, with its unique identifiers, and
will then be alerted by the mobile switch when there is an
incoming telephone call. The handset constantly listens for the
strongest signal being received from the surrounding base
stations. As the user moves around the network, the mobile
device will "handoff" to various cell sites during calls, or
while waiting (idle) between calls it will reselect cell sites.
Cell sites have relatively low-power (often only one or two
watts) radio transmitters which broadcast their presence and
relay communications between the mobile handsets and the switch.
The switch in turn connects the call to another subscriber of
the same wireless service provider or to the public telephone
network, which includes the networks of other wireless carriers.
The dialogue between the handset and the cell site is a stream
of digital data that includes digitized audio (except for the
first generation analog networks). The technology that achieves
this depends on the system which the mobile phone operator has
adopted. Some technologies include AMPS for analog, and D-AMPS,
CDMA2000, GSM, GPRS, EV-DO, and UMTS for digital communications.
Each network operator has a unique radio frequency band.
Controversy
Health controversy
Main article: Mobile phone radiation and health
As with many new technologies, concerns have arisen about the
effects on health from using a mobile telephone. There is a
small amount of scientific evidence for an increase in certain
types of rare tumors (cancer) in long-time, heavy users. More
recently a pan-European study provided significant evidence of
genetic damage under certain conditions. Some researchers also
report the mobile phone industry has interfered with further
research on health risks. So far, however, the World Health
Organization Task Force on EMF effects on health has no
definitive conclusion on the veracity of these allegations. (See
also electromagnetic radiation hazard.) It is generally thought,
however, that RF is incapable of producing any more than heating
effects, as it is considered non-ionizing radiation; in other
words, it lacks the energy to disrupt molecular bonds such as
occurs in genetic mutations.
Sperm production
Mobile phones have also been identified as a (potential) cause
of reduced sperm production in men. Microwaves emitted by the
phones reduce the number, mobility and quality of sperm by
almost half in the heaviest users, to the point where some men
may become infertile, scientists say. This could have
devastating consequences for fertility rates around the world.
Almost a billion people around the world use mobile phones, and
the number is growing. Even a small effect on fertility could
result in millions of men being rendered childless.
Driving controversy
Main article: Mobile phones and driving safety
Another controversial but potentially more lethal health concern
is the correlation with road traffic accidents. Several studies
have shown that motorists have a much higher risk of collisions
and losing control of the vehicle while talking on the mobile
telephone simultaneously with driving, even when using
"hands-free" systems. Other studies have shown that using a
mobile phone while driving poses the same risk as someone
operating a vehicle while under the influence of alcohol. Four
U.S. states and many countries have now restricted or prohibited
the use of mobile phones while driving. In Israel and nearly all
European countries, driving whilst using a hand-held mobile
phone is illegal.
Potential danger during electrical storms
In 2006, it was reported that mobile phone users suffer much
more serious lesions than non-users, in case of being struck by
lightning during an electrical storm. Cell phones do not,
however, present the danger of a land line during an electrical
storm; whereas wires can carry a lightning strike to a nearby
telephone user, cell phone signals are immune to such danger.
Security concerns
Early mobile phones were limited in their security features.
Some problems with these models were "cloning", a variant of
identity theft, and "scanning" whereby third parties in the
local area could intercept and eavesdrop in on calls. Analogue
phones could also be listened to on some radio scanners.
Although more recent digital systems (such as GSM) have
attempted to address these fundamental issues, security problems
continue to persist. Vulnerabilities (such as SMS spoofing) have
been found in many current protocols that continue to allow the
possibility of eavesdropping or cloning.
It should be noted that on a technical level, CDMA is more
secure then GSM and TDMA. This is due to the fact that all calls
are separated onto their own channel and encoded with a unique
encryption code. 1 In all though, digital is much more secure
then analog systems. |
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