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Welcome to Mobile Phone History! This web site was made to educate those who are interesed in cell phones. You can learn about the origin of the cell phone, people who contributed in its invention, how cell phones work, the risks and safety issues of using cell phones, and cell phone structure. The information on this site was taken from the sites listed in the Bibliography. You can find more information at those web sites.
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.
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.
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.
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.
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 can not 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.