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cell phones work

You've seen them, perhaps you've used one. Each day something like 100,000 people around the world sign up for and start using a cellular phone. Therefore it is likely that you or someone you know has a cell phone and uses it on a regular basis. They are such great gadgets - with a cell phone you can talk to anyone on the planet from just about anywhere (80% of the U.S. has coverage).

But have you ever wondered how a cell phone works? Or what happens when you talk on one? Or how a call gets routed to a regular phone? we will discuss the technology behind cell phones so that you can see how amazing they really are.

One of the most interesting things about a cell phone is that it is really a radio - an extremely sophisticated radio, but a radio nonetheless. A good way to understand the sophistication of a cell phone is to compare it to a CB radio or a walkie-talkie. A CB radio is a simplex device. That is, two people communicating on a CB radio use the same frequency, so only one person can talk at a time. A cell phone is a duplex device, so it uses one frequency for talking and a second, separate frequency for listening. A CB radio has 40 channels. A cell phone can communicate on 1,664 channels. Cell phones also operate within cells and they can switch cells as they move around. Cells give cell phones incredible range. A walkie-talkie can transmit perhaps a mile. A CB radio, because it has much higher power, can transmit perhaps 5 miles. Someone using a cell phone, on the other hand, can drive clear across a city and maintain a conversation the entire time. Cells are what give a cell phone its incredible range.