HOW DO CELL PHONE WORK?
By Nelson Oduro
ISC 110
INTRODUCTION
Nowadays, cell phones are everywhere.
 Cell phones are being carried by almost everyone
around the world including children, teenagers,
adults, as well as grandparents.
 Phone companies are one of the fastest growing
businesses on the market. This is because technology
is blooming.
 Every now and then, there are new phones that are
released in the market. Marketing strategies like new
features are being used to update phones to make the
phone looks different.
 Phones nowadays can perform many tasks such as
web browsing, making phone, checking email, GPS
locations, and more.

CONTINUE….
There were about 87% adults own cell phones in
2012 excluding teenagers.
 Statistics predicted that in 2013, the population of
those who use phones would increase.
 Also according to the article “how do cell phones
work”, there were about seven billion people that
were using cellphones worldwide.

WHAT IS A CELL PHONE AND HOW DOES IT
WORK?
A cell phone is mainly a two way radio, which
consists of a radio transmitter and a radio
receiver.
 As we talk to someone on a cell phone, the phone
converts the voice into an electrical signal, which
is then transmitted through radio waves to the
nearest cell tower.

CONTINUE…..
The network of cell towers then communicates
the radio wave to the person’s cell phone, which
transforms it to an electrical signal and then
back to sound again.
 Cell phones use radio waves to communicate.
Radio waves transport digitized voice or data in
the form of wavering electric and magnetic fields,
called the electromagnetic field (EMF).
 The rate of alternation is called frequency.

Radio waves transport the information and travel in air
at the speed of light.
 There are several directions which cell phone radio
waves are transmitted. All waves are absorbed and
reflected through surrounding objects before the waves
reach the nearest cell tower.
 Also most cell phones have at least one built in radio
antenna in order to transmit or receive radio signals. An
antenna transforms an electric signal to the radio wave
(transmitter) and vice versa (receiver).
 Some cell phones use more than one transmitter and
receiver antenna, while in some cell phones only has one
transmitter and receiver antenna. For example, the
iPhone has more than one transmitter and receiver
antenna.

An antenna helps us to transmit and receive frequencies
of radio waves, but in some older generation phones, some
antennas were external or extractable. Due to the
blooming of technology, modern phones have compactable
antennas inside them.
 All metal components in the device like the circuit board
metal frame in the iPhone can cooperate with the spread
antennas and also contribute to the outline transmitted
signal.
 In every two to three miles, there is a phone tower that
helps the phone to communicate with others to get
service.
 Cell phones transmit to towers, which then connects you
to the normal land based telephone system to route a
phone call.

A large city has hundreds of towers. Each carrier in
each city runs a central office also known as the Mobile
Telephone Switching Office (MTSO).
 The MTSO is a switch that controls all the operation
system of a cellular system. When you power up a
phone, it listens for special frequencies (control
channel) that the phone and tower use to talk to one
another.
 If there is no control channel, a phone displays a
message no service because it knows it is out of range
(The Physics of Cell Phones, 2003).
 A phone transmits a registration request so that the
MTSO keeps track of the phone’s location in the
database.

It is important for the MTSO to know the cell phone
one is using when the phone cell phone is about to ring.
 When MTSO gets a call, it tries to find the owner of
the by looking into the database to see which cell tower
you are near.
 MTSO also chooses a frequency pair that a phone will
use in that cell to take the call.
 MTSO communicates with your phone over the control
channel to tell it what frequencies to use.

When your phone and the tower switch on those
frequencies you are connected and talking.
 Lastly, as one move toward the edge of the cell range,
the cell tower notes a diminishing signal.
 The diminishing signal indicates that it is time for the
control channel to hand off you to the next cell tower.

ADVANTAGES OF A CELL PHONE
Cell phones are small and easy to carry around.
Modern digital cell phones can process millions of
calculations per second in order to compress and
decompress the voice stream.
 Cell phones have full duplex, meaning you can
use one frequency for talk and other frequency
for listening.
 Other advantages of cell phones are that you can
store information, make task or to do lists, keep
track of appointments, and set reminders.

CONTINUE….
Cell phones have a built-in calculator for math,
you can send, receive calls, get information for a
variety of sources, such as, news, entertainment,
stock quotes, and play simple games.
 Cell phones have great influence in our everyday
life and are convenient to have around. Cell
phones are a faster and more effective way to
transfer information.

DISADVANTAGES OF A CELL PHONE
Cell phones physically have non-repairable internal
parts that can corrode. For example if a cell phone
gets wet, it may damage the internal parts.
 Extreme heat in a car can damage the battery or the
cell phone electronics and extreme cold may cause a
momentary loss of the screen display.
 In the tall building rage, it is hard to gain service
because the cell phone might not communicate well
with the cell towers .

There are reasons to think that cell phones may
cause cancer of the ear or brain tumors.
 to the brain.

The more an individual uses cell phones and the
greater the number of years used by the person, the
greater the risk of brain tumors.
 However, there has been doubt of phone companies
that there are no links to cancer even though the
phones radiations do not have any connection to the
electrical activity

REFERENCE
"How Do Cell Phones Work?" Pong Making the Case for Cell Phone
Radiation Protection RSS. N.p., n.d. Web. 01 Dec. 2013. Retrieved
from http://www.pongcase.com/blog/cell-phones-work
"The Physics of Cell Phones." 03.04.07: The Physics of Cell Phones.
N.p., n.d. Web. 01 Dec. 2013. Retrieved from
http://www.yale.edu/ynhti/curriculum/units/2003/4/03.04.07.x.html
"How a Cell Phone Works." How a Cell Phone Works. N.p., n.d.
Web. 01 Dec. 2013. Retrieved from
http://iml.jou.ufl.edu/projects/fall04/keith/Works.htm
"Guide Print Email." Understanding Wireless Telephone Coverage
Areas. N.p., n.d. Web. 01 Dec. 2013. Retrieved from
http://www.fcc.gov/guides/understanding-wireless-telephonecoverage-areas