Also known as Cellular Radio Telephones, cell phones are wireless and portable. As time passes they get

smaller and with more functions. When the first ones came out they were as big as “bricks” and now they

fit inside your hand. Nowadays, cell phones can have access to internet, mail, videoconferencing, games, etc.

You can talk almost from anywhere in the world. Most of the people need them for work or just use them

as a communication device.

They don't need power outlets or any type of cable.

Cell Phones use and need cellular towers to be able to communicate. These towers can receive signals from 1.5 km and up to 56 km . The spaces that these towers cover are called cells. Many towers can be in the same cell space so that they can manage when there are many cell phone users at the same place. When you are moving and using a cell phone, as you pass from cell to cell, you also pass the cell phone signal to the next tower so your call is not interrupted. The towers send the signal to a switching station which is connected to the telephone system of that company.

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