Cell Phone History

1st cell phone to today

Origin

Cell phones may be new devices, but they originated in the 1920’s. Radios were used since 1921. Features were put into these radios in the 1940’s, and they were used by police. The concept of the cellular phone was developed in 1947 which originated from the mobile car phone. The concept of the cellular phone was produced by Bell Laboratories.

1st cell phone by Motorola

The first actual cell phone was made in 1973 by Martin Cooper of Motorola and other assisting inventors who used the idea of the car phone and applied the technology necessary to make a portable cell phone possible. Cell phones were first made available to the public in 1984. Back then, they were very large, expensive instruments.

The Federal Communications Commission made a regulation that limited radio-spectrum frequencies. This is the reason only twenty-three simultaneous conversations were possible in the same service area. In 1968 the FCC decided to increase the frequencies to allow research for better connections. The FCC worked together with AT&T and Bell Towers to establish broadcast towers. The towers were small with low power and covered a “cell” that was a few miles in radius, but actually covered a larger area. This allowed calls to pass from tower to tower.

Inventors

Martin 1st cell phone inventor

Martin Cooper pioneered Motorola’s research for cellular phones. He was raised in Chicago, and attended the Institute of Technology in Illinois where he obtained a degree in electrical engineering. After working for the navy he also worked for a telecommunications company, and got a job with Motorola in 1954. Cooper worked on the first portable handheld police radio. He was also the first to ever make a phone call using a cellular Phone.

 Some of the other people that aided in the invention of cell phones include Richard W. Dronsuth, Albert J. Mikulski, Charles N. Lynk Jr., James J. Mikulski, John F. Mitchell, Roy A. Richardson, and John H. Sangster.

Motorola 1st cell Phone Company

How They Work

Cell phones originated from the radio, and evolved into the telephone. Each city is divided up into cells that allow frequencies to be transferred. Each cell has a hexagonal shape with a tower in the center (base station), and a building that contains radio equipment.

internal part's

Every carrier within a city uses the same central office, the Mobile Telephone Switching Office (MTSO). A cell phone carrier is usually allowed about 832 radio frequencies to use per city. With the analog system, one cell phone uses 2 frequencies per phone call, but each cell has about 56 voice channels available which means that 56 cell phones can be in use at one time. This all increases with digital systems and makes cellular phone work more efficiently.

When the cell phone is activated it searches for a System Identification Code (SID) on a control channel. A SID is a different 5 digit number that is assigned. The control channel is responsible for allowing the phone and base station to communicate about call set–up and channel changing. If a control channel cannot be found then the phone is out of range and has “no service”. When the cell phone gets the SID, it is compared to the SID that has already been set in the phone and if they match then this means two cell phones of the same home system have been connected. Also, the cell phone gives off a registration request. The MTSO keeps a record of the phone’s location in order to know what cell it is in when in needs to ring. Once the phone rings and the cell has been determined, the MTSO chooses a frequency pair that the phone uses to take the call. Over the control channel the MTSO communicates with the cell phone to determine which frequencies to use. Then the cell phone and the tower switch with those frequencies and the call is connected. If the cell phone reaches the end of the cell the strength of the signal diminishes so the MTSO allows the 2 base stations to connect and get on a control channel to decide which frequency to switch to.

How it work

Safety and Risks

When the first cell phones were made in 1984, there were many health risks. Cell phones emit radiation that could be harmful. No testing had been done prior to releasing these phones to the public. The radiation could possibly lead to brain cancer with long-term use.

Cellular phones give off an electromagnetic energy which is a type of non-ionizing radiation. This is similar to the radiation naturally found in thunderstorms. The RF electromagnetic energy that cellular phones create can penetrate through a body. The main factors for the depth of penetration and how much is absorbed come from how close the phone is held and how strong its signal is.

It is possible that cell phones can cause serious health issues such as cancer, epileptic seizures or sleep disorders, changes in brain activity, and reaction time, but nothing has been definitely proven

Using a cell phone while driving can increase the risks for accidents. They may interfere with medical devices. These include pacemakers, defibrillators, and hearing aids. Cell phones also interfere with aircraft electronics.

SAR, (specific absorption rate), has a limit of 1.6 watts per kilogram to decrease the health risks.
Hands free phones and devices can be used while driving to prevent traffic accidents, although it is best to refrain from using phones completely while driving.

1st cell phone

Original Structure

The first cellular phones to be created were very large and bulky. This made them difficult to carry around. The first cell phone come to the market in 1984 from Motorola and weighed 2 pounds. It was a DynaTac 8000X which was selling for $3995. A few years later, in 1991 the Motorola MicroTac Lite was created which cost $1000.

Present Structure

The structure of cellular phones has evolved. They have decreased drastically in size and weight. Currently the smallest cell phone in the world weighs slightly more than a pack of cigarettes and is 68 X 38.5 X 22 mm. Cell phones are now so small that they can be carried around more conveniently, but are very easy to loose. They come with numerous features and functions. There are different styles of cell phones such as a flip phone or the slide phone.

It is easy to customize a cell phone by choosing the model, color, style, its features and functions, and size. There are even phone covers that change the face design of the phone. Various accessories are available such as car chargers, belt clips, glowing antennas, and data cables.

Future Cell Phones

Some predict that the cellular phone will completely take over, and wirelines will hardly be used by the year 2010. With the expansion of the wireless lines area codes that distinguish between states will also lose importance.

Future cell Phone

First there are a couple changes that the wireless industry must make. Reception and coverage areas will increase. This way making long distance phone calls from all over the world will be possible without interruption. Technological advancements such as TDMA, CDMA, and GSM already provide clear calls.

Calling restrictions on time will no longer exist so that calls can be made at any time conveniently. More efficient networks that require fewer costs will allow carriers to offer only unlimited calling plans.

References:-

 History Of Cell Phones.

Farley, Tom. "Mobile Phone History.

Bellis, Mary. "Selling The Cell Phone. 

Safety and Safe Use of Cellular Phones. 

Do Cellular Phones Pose Health Risks?. 

Cell Phone Features.

Cellular Phones - Industry Overview.

How Cell Phones Work.

Smallest Cell Phone In The World.

The Future of Cell Phones.

History of Cell Phones.

 Martin Cooper - Inventor of the Cellphone.