I believe everyone reading this article knows what a cell phone is and probably already used one. We all use them everyday calling, sending text messages, accessing the internet, and so on, but how many of us know how do cell phones work ? Let me give you some small info about it.

An interesting feature about a cell phone is the fact that it is actually a radio, a high-tech radio. To better understand the sophisticated mechanism of a cell phone, we will compare it to a walkie talkie radio communication system. The walkie talkie communication system has a simplex type of communication method, by which 2 persons communicate on the same frequency, but only one at a time ( think of the way truck drivers communicate ).

The cell phone is a duplex device, which means it uses a frequency to talk and a separate frequency to listen. A walkie talkie system can have tens of channels while a cell phone can communicate on one thousand six hundred and sixty-four channels.



The mobile phone also operates with cells, which means they can pass from a cell to another while space traveling. The cells represent basics of a cell phone - the geographical area that a mobile phone company is covering. The cells give the cell phones an incredible covering area; a walkie talkie can communicate on a distance from a couple hundred meters up to ten or fifteen kilometer while a phone user can go to any location from a city and keep the conversation on the line - thanks to these cells. When a cell phone passes from a cell to another, a computer monitors this movement at the right moment transferring in the same time the phone call to a new cell and a new frequency; the transfer from a cell to another is so fast the cell phone users can't even notice it.

But how does a cell work? The key to the cellular system is the fact that a city can be split in tiny cells, and cell allow the extensive use of frequencies reused over a city. Reusing the frequencies is the thing that allows millions of people to have their own cell phones. Because cell phones and the base stations use low voltage transmitters, the same frequencies can be reused not only by close cells. Every cell has a base station made out of a tower and a small building that contains the radio equipment. The cells have different sizes depending on the space, the required capacity, etc.



When a cell phone user travels from a country to another, he leaves the cell system of the service provider he belongs to. The cell system allows the passing to another cell system owned by another cell phone service provider This transfer is named roaming.

So now we know how do cell phones work and what is the similarity is between it and the walkie talkie radios; it's not like we evolved that much from the radio, haven't we ?