About the cellular phone repairing:
our experience the most common problem of the cellular mobile phone is probably more on
software problem 60% -70% and the others is hardware 30% - 40%.
What is the difference of
Minor and Major Repair from Software to Hardware?
If the problem of the cellular phone is Software minor or major repair is not difficult to fix, You need only a complete information from our training or this book. We give you the technique how to fix!
If the problem of the cellular phone is Hardware minor or major is difficult
if you are a beginner in mobile phone repairing,
we give you the information how
to do fix uncomplicated. Just read this book and you need more practice to get perfect!!!
And later you will be an Expert Mobile Phone Technician and honest to all your customers.
CELLULAR PHONE: Cellular Telephone is wireless telephone that transmits and receives messages
via radio signals. It enables people to communicate over wide area by using the
network of radio antennas and transmitters arrange in small geographical areas
Cells vary in size and number, based
on the network’s extent. A cellular telephone unit is actually a radio transceiver
--------that is, a transmitter
and receiver in one. Many such units enable the user send and receive txt massages in additional to voice messages. Some provide access to news and information via internet.
Many can store telephone number or other data.
Cellular Telephone is a radio
waves carry a user’s message to an antenna that is connected to a transceiver in the cell in which the user is operating the telephone. The transceiver relay the message
to a mobile telephone switching office (MTSO). The MTSO transmits the message to
a local telephone company, which sends the call to receiving telephone or to a long-distance
company for completion. As the caller moves, the network automatically passes to the call from
one cell to the next cell without
interruption. The tern roaming describes the use of the cellular telephone outside a designation local calling area. Communication
companies whose cellular networks do not cover a large region often share their
networks with one another to offer their customers roaming. To receive call outside the local calling area, a user often must key a code into his or her cellular telephone. This action automatically notifies
the MSTO of the region of the cells
in which user can be reached. The MSTO can then deliver a call by directing the transceiver in those cell
to signal the desired telephone.
Types of the Cellular Telephones.
are three types of cellular telephone. Installed phones are mounted in a vehicle, such as an automobile, and powered by the vehicle’s electrical system. Transportable phones have
their own carrying case and are powered by a battery pack. Portable phones are battery
power units small enough to keep in a coat pocket.
first commercial cellular phone system went into operation in 1983 in the United States. Cellular service is now available in much of the world. Many developing nations have used cellular
technology to provide telephone service in remotes areas without installing phones lines.
See also Wireless Communication.
||Dr Martin Cooper, a former general manager for the systems division
at Motorola, is considered the inventor of the first portable handset and the first person to make a call on a portable cell
phone in April 1973. The first call he made was to his rival, Joel Engel, Bell Labs head of research.|
AT&T's research arm, Bell Laboratories, introduced the idea of cellular communications in 1947. But Motorola and Bell
Labs in the sixties and early seventies were in a race to incorporate the technology into portable devices.
Cooper, now 70, wanted people to be able to carry their phones with them anywhere.
While he was a project manager at Motorola in 1973, Cooper set up a base station in New York with the first working prototype
of a cellular telephone, the Motorola Dyna-Tac. After some initial testing in Washington for the F.C.C., Mr. Cooper and Motorola
took the phone technology to New York to show the public.
First Cellphone (1973)|
Name: Motorola Dyna-Tac
Size: 9 x 5 x 1.75
Weight: 2.5 pounds
Number of Circuit Boards: 30
Talk time: 35
Recharge Time: 10 hours
Features: Talk, listen, dial
In 1973, when the company installed the base station to handle the first public demonstration of a phone call over the
cellular network, Motorola was trying to persuade the Federal Communications Commission to allocate frequency space to private
companies for use in the emerging technology of cellular communications. After some initial testing in Washington for the
F.C.C., Mr. Cooper and Motorola took the phone technology to New York to show the public.
On April 3, 1973, standing on a street near the Manhattan Hilton, Mr. Cooper decided to attempt a private call before going
to a press conference upstairs in the hotel. He picked up the 2-pound Motorola handset called the Dyna-Tac and pushed the
"off hook" button.
The phone came alive, connecting Mr. Cooper with the base station on the roof of the Burlington Consolidated Tower (now
the Alliance Capital Building) and into the land-line system. To the bewilderment of some passers-by, he dialed the number
and held the phone to his ear.
Who is he?
Cooper grew up in Chicago and earned a degree in electrical engineering at the Illinois Institute
of Technology. After four years in the navy serving on destroyers and a submarine, he worked for a year at a telecommunications
Hired by Motorola in 1954, Mr. Cooper worked on developing portable products, including the first portable handheld police
radios, made for the Chicago police department in 1967. He then led Motorola's cellular research.
September 23, 2003Martin Cooper on the First Cell Phone Call
Inventor of the modern cell phone Martin Cooper recalls to the press, "As I walked down the street while talking on
the phone, sophisticated New Yorkers gaped at the sight of someone actually moving around while making a phone call. Remember
that in 1973, there weren't cordless telephones, let alone cellular phones."
Martin Cooper talks about the first cell phone call.
April 3, 2003 marked the 30th anniversary of the first public telephone call placed on a portable cellular phone. Martin
Cooper ( now chairman, CEO, and co-founder of ArrayComm Inc) placed that call on April 3, 1973, while general manager of Motorola's
Communications Systems Division. It was the incarnation of his vision for personal wireless communications, distinct from
cellular car phones. That first call, placed to Cooper's rival at AT&T's Bell Labs from the streets of New York City,
caused a fundamental technology and communications market shift toward the person and away from the place.
"People want to talk to other people - not a house, or an office, or a car. Given a choice, people will demand the freedom
to communicate wherever they are, unfettered by the infamous copper wire. It is that freedom we sought to vividly demonstrate
in 1973," said Martin Cooper.
Martin Cooper added, "As I walked down the street while talking on the phone, sophisticated New Yorkers gaped at the
sight of someone actually moving around while making a phone call. Remember that in 1973, there weren't cordless telephones,
let alone cellular phones. I made numerous calls, including one where I crossed the street while talking to a New York radio
reporter - probably one of the more dangerous things I have ever done in my life."
Following the April 3, 1973, public demonstration, using a "brick"-like 30-ounce phone, Cooper started the 10-year process
of bringing the portable cell phone to market. Motorola introduced the 16-ounce "DynaTAC" phone into commercial service in
1983, with each phone costing the consumer $3,500. It took seven additional years before there were a million subscribers
in the United States. Today, there are more cellular subscribers than wireline phone subscribers in the world, with mobile
phones weighing as little as 3 ounces.
Martin Cooper Today
Martin Cooper's role in conceiving and developing the first portable cellular phone directly impacted his choice to found
and lead ArrayComm, a wireless technology and systems company founded in 1992. ArrayComm's core adaptive antenna technology increases the capacity
and coverage of any cellular system, while significantly lowering costs and making speech more reliable. This technology addresses
what Cooper calls "the unfulfilled promise" of cellular, which should be, but still isn't as reliable or affordable as wired
ArrayComm has also used its adaptive antenna technology to make the Internet "personal" by creating the i-BURST Personal
Broadband System, which delivers high-speed, mobile Internet access that consumers can afford.
"It's very exciting to be part of a movement toward making broadband available to people with the same freedom to be anywhere
that they have for voice communications today," said Martin Cooper. "People rely heavily on the Internet for their work, entertainment
and communication, but they need to be unleashed. We will look back at 2003 as the beginning of the era when the Internet
became truly untethered."
How the Cellular System Works
Every cellular system digital or analog
is comprised of four parts.
1 ) Cells and cell sites ( base stations )
2 ) Switching station ( mobile telephone
switching office or MTSO )
3 ) System operator and its local office
4 ) Cellular telephones
The heart of the system is made up of individual radio coverage
areas called " cells. " Each cell is a self-contained calling area. Within the cell, a cell site is strategically positioned
as a base station for receiving, sending and routing the radio signals of cellular phone calls. Because the cellular system
is a radio system, no exact boundary can be drawn on a map. In most cases calls can be place and received throughout the service
area, except for certain enclosed areas such as underground parking garages. The No Svc ( No Service ) indicator will illuminate
on the cellular phone when in one of those areas or is outside of the service area. The cell site's transmitter is low powered
and does not reach much beyond that cell's boundaries. That makes it possible to reuse channels ( frequencies ) - a given
channel can be used at the same time in different cells, as long as the cells do not border one another, without causing signal
interference. This is particularly valuable in urban areas where lots of cellular phones are in use at the same time. All
cell sites are connected to the Mobile Telephone Switching Office ( MTSO ), which provides connection into the Public Switched
Telephone network ( PSTN ) - the local telephone company. The MTSO also provides other central functions, including call processing,
traffic management, and transferring calls as a phone moves between cell sites.
Making a Call
When a cellular user makes a call from a cellular phone, radio signals are transmitted to the cell site. The cell site
alerts the Mobile Telephone Switching Office ( MTSO ) switching station. The MTSO, in turn, provides an open channel ( frequency
) and connects the call to the Public Switched Telephone Network ( PSTN ). The PSTN put the call through to the number to
be reached. This process takes the same amount of time that it takes to make a call from a land line phone.
These are the steps that occur when you receive a call on a cellular phone. A call placed to a cellular phone may come
from either a land line phone or another cellular phone. Whichever the source, the MTSO is notified that a call has been placed
to a specific cellular telephone number. At this point, the MTSO searches for the correct cellular phone by sending out data
over the radio waves. Cellular phones that are in standby mode ( i.e., turned on but not being used in a call ) continuously
scan the radio waves being transmitted by the MSTO. If a phone " hears " its telephone number, it sends back a signal that
informs the closest cell site of its Electronic Serial Number ( ESN ) and its telephone number ( Mobile Identification Number
or MIN ). The cell site passes this information to the MTSO, where the ESN and MIN are verified and a channel ( frequency
) is assigned for the call. The cellular phone receives the message directing it to tune to the correct voice channel. The
cell site makes the voice channel available, and the call is completed.
Hand-off is the transfer of a call from one cell site
to another as the cellular phone moves through the service coverage area. The cell site warns the MSTO that the mobile's signal
strength is falling below a predetermined level. The MTSO then alerts all cell sites bordering on the first one. They measure
the mobile's transmitting signal and report back to the MTSO. The MTSO, which is programmed to select the site receiving the
strongest signal, then switches the call from the weak cell to the strongest cell without interrupting the call. The whole
process takes a fraction of a second, and the caller usually is unaware of it. Such hand-offs may occur several times during
a single conversation as the caller moves through the coverage area.
Roaming is a service offered by most cellular
service providers that allows subscribers to use cellular service while traveling outside their home service area. When they
are outside their home service area and come within range of another cellular system, the ROAM indicator on the cellular phone
will light to show that they are in range. Typically there are two cellular system operators serving a specific area. One
is a wireline ( local phone company ) and the other is non-wireline. When starting cellular telephone service, subscribers
are assigned to one or the other. When they roam ( operate outside their home system ), their cellular phone will seek service
from the same type of cellular system as the one they subscribe to at home. But if that type is not available where they are
roaming, the phone will try to obtain service from the non-home-type system. A blinking light indicates a non-home-type system.
There is an extra charge for calls placed while roaming.