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ICANEWS
Agosto 2004, Año 1 # 4 |
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| Cellular Confusion Digital, Analogic,
GSM? |
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| by Hernan Casanova
hc@interdevelopers.com |
As you talk
with your sweetheart on the cellular trying
to explain why you are late, you probably don’t stop
to consider the technological wonders involved
in making this conversation possible. Here is how!!!! (If
you care to read, hey! you are late anyway!!!).
Basically, cellular phones are small radios that connect to
a network of antennae at a high frequency
to prevent interference. Each antenna covers
an area that determines the range of the
"cell" (That’s where the name cellular comes
from), and while you move around, you are passed from one
cell to another to keep your call going. These cells can then
connect you to the number you dialed.
The concept of mobile communications is not that new. In 1921
the Detroit Michigan Police Dept. made the earliest significant
use of mobile radio in a vehicle in the United States. The
first public mobile telephone system in the U.S. was inaugurated
in St. Louis, Missouri in 1945. In 1969 the "Improved
Mobile Telephone System" (IMTS) was introduced and became
the standard for mobile telephone service in the U.S. Only
in 1981 FCC issued standard rules for the cellular industry.
In Argentina cellular phones were introduced at the end of
the 80’s (remember Movicom?) with heavy sets and limited
range, with a reduced number of customers.Growth
was explosive. In 1999 there were 3 million cellular lines
in Argentina, in May 2004 there were more than 9 millions,exceeding
the installed landlines.
Cell phones today in Argentina use different technologies
depending on the company and telephone used. These technologies
are commonly known as "Analog", "Digital"
and "GSM". Each of them comprises different subgroups.
For example analog systems include AMPS, N-AMPS and some others.
Digitals can be CDMA, TDMA etc. So, what is the meaning of
this mixture of letters that most of us human don’t
even bother to understand? Let’s have
a brief look:
Analog system: They were built in the early 1980's. based
in the FDMA technology ("frequency division multiple
access"). These are the least efficient
cellular networks since each analog channel can only be used
by one user at a time. As they need more power, they also
consume more battery than digitals.
Another problem: calls can be easily intecepted with minimum
technology. With a radio scanner it is easy to listen to cellular
calls. There are many horror stories about cellular calls
being intercepted and recorded by spying agencies in Argentina.
So if you use an analog phone be careful when you speak about
your visiting relatives!
Given these drawbacks, it is easy to see
why analog networks are being replaced by newer digital networks
such as TDMA and CDMA. In Argentina all the new networks being
built are of digital nature.
Digital systems: As the name indicates, digital systems send
the voice information digitally, as in a computer. This allows
for the voice to be compressed and "cleaned" for
better reception. The call is also encrypted, making it much
more difficult to be intercepted (remember the horror stories?).
Digital also allows for easy integration with personal communication
systems (PCS) such as hand held devices, palm, etc.
GSM: Stands for Global System
for Mobile Communications. GSM is an open,
non-proprietary system that is constantly evolving. It is
basically a digital system, but with more advantages, such
as international roaming capability. This allows for example,
a Spanish tourist to receive calls while visiting Argentina.
It also provides for better use of wide band
technolgies such as on-line services, internet connection
etc. In Argentina, this technology is pretty new, less than
2 years, but it is gaining ground quickly.
You can recognize GSM phones by the "chip" inside,
as seen in the TV commercials, containing all the phone information.
If you want to change phones in the future, just take the
chip and install it in the new one with all the info, contacts,
ringtones etc. Cool, eh?. An important problem with GSM in
Argentina is that the network is being built, and there are
still many areas where you don’t get service, depending
on the company . I know, this is happening to me! I have to
carry two phones , a GSM and a digital one to be fully connected!
We can expect to see in the future newer technologies such
as 3GSM, (3G is third generation), that is the union of the
computer, the telephone, the video camera, and the internet:
all in your front pocket.
Hope this helped you to understand a little better why your
wife is screaming so CLEARLY on the phone
because it is 3 AM and you are not home!!!
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| Glossary |
sweetheart:
amorcito.
wonders: maravillas.
antennae: antenas.
to prevent: impeder.
range: alcance.
dialed: discado.
customers: clientes.
landlines: líneas terrestres.
comprises: incluye.
bother: molestarse.
the least: los menos.
drawbacks: desventajas.
wide band: banda ancha.
gaining ground: ganando terreno.
screaming: gritando.
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