Mobile Phone
Content
Mobile phone
From Wikipedia, the free encyclopedia
Siemens AX72.
Galaxy Nexus, an example of a smartphone
A mobile phone (also known as a wireless phone, cell phone, or cellular telephone[1]) is a very
small portable radio telephone.
The mobile phone can be used to communicate over long distances without wires. It works by
communicating with a nearby base station (also called a "cell site") which connects it to the main
phone network. As the mobile phone moves around, if the mobile phone gets too far away from the
cell it is connected to, that cell sends a message to another cell to tell the new cell to take over the
call. This is called a "hand off," and the call continues with the new cell the phone is connected to.
The hand-off is done so well and carefully that the user will usually never even know that the call
was transferred to another cell.
As mobile phones became more popular, they began to cost less money, and more people could
afford them. Monthly plans became available for rates as low as US$30 or US$40 a month. Cell
phones have become so cheap to own that they have mostly replaced pay phones and phone
booths except for urban areas with many people.
Many mobile phones are "smartphones". As well as making voice calls, they can be used as
computers.
Contents
[hide]
1 History
2 Technology
3 Shapes
4 How mobile phones work
5 Networks and payment
6 Smartphones
7 References
History[change | change source]
Mobile phones in the 1950s through 1970s were large and heavy, and most were built into cars. In
the late 20th century technology improved so people could carry their phones easily.
Although Dr. Martin Cooper from Motorola made the first call using a mobile phone in 1973, it did not
use the type of cellular mobile phone network that we use today.
The first mobile phone networks were created in the late 1970s in Japan. Now almost
all urban areas, and many country areas, are covered by mobile phone networks.
Inside a mobile phone
Technology[change | change source]
A cell phone combines technologies, mainly telephone, radio, and computer.
Cell phones work as two-way radios. They send electromagnetic microwaves from base station to
base station. The waves are sent through antennas. This is called wireless communication.
Early cell telephones used analog networks. They became rare late in the 20th century. Modern
phones use digital networks.
The first digital networks are also known as second generation, or 2G, technologies. The most used
digital network is GSM (Global System for Mobile communication). It is used mainly
in Europe and Asia, while CDMA (Code-Division Multiple Access) networks are mainly used in North
America. The difference is in communication protocol. Other countries like Japan have different 2G
protocols. Some 2G networks are still used. 3G are more common, and some places have 4G.
The radio waves that the mobile phone networks use are split into different frequencies. The
frequency is measured in Hz. Low frequencies can send the signal farther. Higher frequencies
provide better connections and the voice communications are generally clearer. Four main
frequencies are used around the world: 850, 900, 1800 and 1900 MHz. Europe uses 900 and
1800 MHz and North America uses 850 and 1900 MHz.
Today there are mobile phones that work on two, three or four frequencies. The most advanced
phones work on all frequencies. They are called 'world' phones and can be used everywhere.
Shapes[change | change source]
There are different kinds of phones. A flip phone flips open, and is best for calling. A bar phone is
shaped like a candy bar, and the keys and screen are on one face. A slate phone is a phone that has
almost no buttons, and uses a touchscreen. Most smartphones are slates. A slider phone slides on
rails. It can slide out number keys or a mini keyboard, but some do both. A swivel spins on an axle.
How mobile phones work[change | change source]
When a mobile phone is switched on, it finds and connects to a nearby mobile phone base station.
Computers in the base station check if the phone is allowed to use the network. The base station
covers what is called a cell and a phone can move between different cells, but will only ever
communicate with one cell at a time. This is why mobile communications are sometimes called
cellular communications.
Once connected to a cell, the mobile phone can make calls. Because the network knows that the
phone is connected to that particular cell, it can also route calls to the mobile phone. Sometimes the
radio connection to the cell is lost, for example when you go underground. This means the phone
cannot make or receive calls until the connection is made again.
Networks and payment[change | change source]
The network is the company that provides the phone service. In most areas there will be more than
one mobile network. Customers choose networks based on how well the different networks work in
their area, or by price.
There are two main ways to pay for mobile phone calls:
1. Contract
If you pay by contract you will pay the network money every month so that you can make
calls. Usually you can talk for a lot of time for the monthly fee, but if you do not use the
phone a lot you still pay the same money.
2. Pay as you use
If you pay as you use, you will pay for a fixed amount of call time credit which you then use
up when phoning people. Once the credit is used up you must buy some more to use the
phone. This can be cheaper if you do not use the phone a lot.
Some digital mobile phones need a separate microchip, called a Subscriber Identity Module or SIM,
to work. The SIM has information like the phone number and payment account and this is needed to
make or receive calls. The SIM may be supplied by the same company as the phone, or a different
one. Sometimes you can change the network by using a SIM from another network, but some
companies do not want this to happen and they lock the phone so that you have to use their SIM.
This type of phone uses GSM signals.
The others have a special radio inside them that only makes phone calls when the phone is
activated. When someone buys a contract, the network gives them a code, that if they enter it into
the phone, the phone will then make calls. It is almost always impossible to switch to a different
network's code on this type of phone. This type of phone is called CDMA.
Smartphones[change | change source]
Many 21st century mobile phones are smartphones. These phones can be used for email, browsing
the internet, playing music and games,and many other functions that computers can perform. This is
because mobile phones basically are smallcomputers. Older phones also used computer
technology, but lacked many of the parts of a computer that were too big to fit into a phone. Modern
phone makers have been able to use smaller parts. Most smartphones are also GPS receivers
anddigital cameras.
For more details, see Smartphone
Wikimedia Commons
hasmedia related to: Mobile
phone
References[change | change source]
1.
Jump up↑ Ulyseas, Mark (2008-01-18). "Of Cigarettes and Cellphones". The Bali Times.
Retrieved 2008-02-24.
Category:
Mobile phones
From Wikipedia, the free encyclopedia
Siemens AX72.
Galaxy Nexus, an example of a smartphone
A mobile phone (also known as a wireless phone, cell phone, or cellular telephone[1]) is a very
small portable radio telephone.
The mobile phone can be used to communicate over long distances without wires. It works by
communicating with a nearby base station (also called a "cell site") which connects it to the main
phone network. As the mobile phone moves around, if the mobile phone gets too far away from the
cell it is connected to, that cell sends a message to another cell to tell the new cell to take over the
call. This is called a "hand off," and the call continues with the new cell the phone is connected to.
The hand-off is done so well and carefully that the user will usually never even know that the call
was transferred to another cell.
As mobile phones became more popular, they began to cost less money, and more people could
afford them. Monthly plans became available for rates as low as US$30 or US$40 a month. Cell
phones have become so cheap to own that they have mostly replaced pay phones and phone
booths except for urban areas with many people.
Many mobile phones are "smartphones". As well as making voice calls, they can be used as
computers.
Contents
[hide]
1 History
2 Technology
3 Shapes
4 How mobile phones work
5 Networks and payment
6 Smartphones
7 References
History[change | change source]
Mobile phones in the 1950s through 1970s were large and heavy, and most were built into cars. In
the late 20th century technology improved so people could carry their phones easily.
Although Dr. Martin Cooper from Motorola made the first call using a mobile phone in 1973, it did not
use the type of cellular mobile phone network that we use today.
The first mobile phone networks were created in the late 1970s in Japan. Now almost
all urban areas, and many country areas, are covered by mobile phone networks.
Inside a mobile phone
Technology[change | change source]
A cell phone combines technologies, mainly telephone, radio, and computer.
Cell phones work as two-way radios. They send electromagnetic microwaves from base station to
base station. The waves are sent through antennas. This is called wireless communication.
Early cell telephones used analog networks. They became rare late in the 20th century. Modern
phones use digital networks.
The first digital networks are also known as second generation, or 2G, technologies. The most used
digital network is GSM (Global System for Mobile communication). It is used mainly
in Europe and Asia, while CDMA (Code-Division Multiple Access) networks are mainly used in North
America. The difference is in communication protocol. Other countries like Japan have different 2G
protocols. Some 2G networks are still used. 3G are more common, and some places have 4G.
The radio waves that the mobile phone networks use are split into different frequencies. The
frequency is measured in Hz. Low frequencies can send the signal farther. Higher frequencies
provide better connections and the voice communications are generally clearer. Four main
frequencies are used around the world: 850, 900, 1800 and 1900 MHz. Europe uses 900 and
1800 MHz and North America uses 850 and 1900 MHz.
Today there are mobile phones that work on two, three or four frequencies. The most advanced
phones work on all frequencies. They are called 'world' phones and can be used everywhere.
Shapes[change | change source]
There are different kinds of phones. A flip phone flips open, and is best for calling. A bar phone is
shaped like a candy bar, and the keys and screen are on one face. A slate phone is a phone that has
almost no buttons, and uses a touchscreen. Most smartphones are slates. A slider phone slides on
rails. It can slide out number keys or a mini keyboard, but some do both. A swivel spins on an axle.
How mobile phones work[change | change source]
When a mobile phone is switched on, it finds and connects to a nearby mobile phone base station.
Computers in the base station check if the phone is allowed to use the network. The base station
covers what is called a cell and a phone can move between different cells, but will only ever
communicate with one cell at a time. This is why mobile communications are sometimes called
cellular communications.
Once connected to a cell, the mobile phone can make calls. Because the network knows that the
phone is connected to that particular cell, it can also route calls to the mobile phone. Sometimes the
radio connection to the cell is lost, for example when you go underground. This means the phone
cannot make or receive calls until the connection is made again.
Networks and payment[change | change source]
The network is the company that provides the phone service. In most areas there will be more than
one mobile network. Customers choose networks based on how well the different networks work in
their area, or by price.
There are two main ways to pay for mobile phone calls:
1. Contract
If you pay by contract you will pay the network money every month so that you can make
calls. Usually you can talk for a lot of time for the monthly fee, but if you do not use the
phone a lot you still pay the same money.
2. Pay as you use
If you pay as you use, you will pay for a fixed amount of call time credit which you then use
up when phoning people. Once the credit is used up you must buy some more to use the
phone. This can be cheaper if you do not use the phone a lot.
Some digital mobile phones need a separate microchip, called a Subscriber Identity Module or SIM,
to work. The SIM has information like the phone number and payment account and this is needed to
make or receive calls. The SIM may be supplied by the same company as the phone, or a different
one. Sometimes you can change the network by using a SIM from another network, but some
companies do not want this to happen and they lock the phone so that you have to use their SIM.
This type of phone uses GSM signals.
The others have a special radio inside them that only makes phone calls when the phone is
activated. When someone buys a contract, the network gives them a code, that if they enter it into
the phone, the phone will then make calls. It is almost always impossible to switch to a different
network's code on this type of phone. This type of phone is called CDMA.
Smartphones[change | change source]
Many 21st century mobile phones are smartphones. These phones can be used for email, browsing
the internet, playing music and games,and many other functions that computers can perform. This is
because mobile phones basically are smallcomputers. Older phones also used computer
technology, but lacked many of the parts of a computer that were too big to fit into a phone. Modern
phone makers have been able to use smaller parts. Most smartphones are also GPS receivers
anddigital cameras.
For more details, see Smartphone
Wikimedia Commons
hasmedia related to: Mobile
phone
References[change | change source]
1.
Jump up↑ Ulyseas, Mark (2008-01-18). "Of Cigarettes and Cellphones". The Bali Times.
Retrieved 2008-02-24.
Category:
Mobile phones
