How does a cell phone work?

Inside your cell phone, there is a compact speaker, a microphone, a keyboard, a display screen, and a powerful circuit board with microprocessors that make each phone a miniature computer. When connected to a wireless network, this bundle of technologies allows you to make phone calls or exchange data with other phones and computers around the world. The components operate so efficiently that a lightweight battery can power your phone for days.

Today, cell phones fit in the palm of your hand, weigh only a few ounces, and offer features such as color graphics, musical ring tones and voice-activated dialing. Only a few years ago, the electronics in this sleek device would have filled a large briefcase.

With wireless data services, you can receive faxes, browse the Internet, send and receive email or play video games-all on your cell phone. Some even include built-in digital cameras, spreadsheet software, GPS location services and music features.

A cell phone is really a radio-a very sophisticated and versatile radio. Much like a walkie-talkie, a cell phone receives and sends radio signals. Because these radios connect into a network, cell phones offer much more-the ability to call any telephone anywhere in the world, Internet access and data services.

Wireless networks operate on a grid that divides cities or regions into smaller cells. One cell might cover a few city blocks or up to 250 square miles. Every cell uses a set of radio frequencies or channels to provide service in its specific area. The power of these radios is controlled in order to limit the signal's geographic range. Because of this, the same frequencies can be re-used in nearby cells. So, many people can hold conversations simultaneously in different cells throughout the city or region, even though they are on the same channel.

In each cell, there is a base station consisting of a wireless antenna and other radio equipment. The wireless antenna in each cell links callers into the local telephone network, the Internet or another wireless network.

No longer just big radio towers, wireless antennas can be mounted in church steeples, on trees and flagpoles, and on top of tall buildings. Many are no larger than stereo speakers. In rural areas, taller antennas send signals further distances to better serve users who are more spread out.

Wireless antennas transmit signals just like your local radio station. And just like your car radio, these radio signals can be obstructed by trees, tall buildings and even weather.

When you turn on your cell phone, it searches for a signal to confirm that service is available. Then the phone transmits certain identification numbers, so the network can verify your customer information-such as your wireless provider and phone number.

If you are calling from a cell phone to a wired phone, your call travels through a nearby wireless antenna and is switched by your wireless carrier to the traditional landline phone system. The call then becomes like any other phone call and is directed over the traditional phone network, and to the person you are calling.

If you are calling another cell phone, your call may go through the landline network to the recipient's wireless carrier, or it might be routed within the wireless network to the cell site nearest the person you called.

If you're calling someone further away, your call will be routed to a long distance switching center, which relays the call across the country or around the world through fiber-optic cables.

All of this takes place in a few seconds-before you say "hello."

Most cell phones use digital technology, which converts your voice into the binary digits 0 and 1-much like a music CD. These small packets of data are relayed through wireless networks to the receiving phone. On the other end, the conversion process is reversed and the person you are calling hears your voice.

But what makes your phone mobile? Say you're talking on your cell phone while walking down the street. The wireless network senses when your signal is getting weaker and hands off your call to an antenna with a stronger signal. Using smaller cells enables your phone to use less power and keep a clear signal as you move. Even when you're not talking, your cell phone communicates with the wireless antenna nearest to you. So, it's ready to connect your call at any time.

If you travel outside your home area and make a call, another wireless carrier may provide service for your cell phone. That provider sends a signal back to your home network, so you can send and receive calls as you travel. This is called roaming. Roaming is key to mobile communications, as wireless providers cooperate to provide callers service wherever they go.

Because the shape and size of cells vary, there may also be empty spaces between the coverage areas of two or more cells. These gaps or dead spots can also be caused by trees, tall buildings or other obstructions that block your wireless signal from reaching a nearby antenna. If a local government or landowner won't allow placement of a wireless antenna, that too creates a dead spot.

A cell phone is actually a computer connected to a radio. Thus, it works much like your personal computer does to send and receive information. Digital technology is used to convert data, such as short messages, e-mail or digital pictures, into small packets of 0's and 1's. These packets are also transmitted securely over wireless systems.

As the wireless industry converts to packet-based networks, utilizing the same technology as the Internet, wireless data services continue to expand. Today wireless networks operate at data speeds five to ten times greater than dial-up telephone or earlier wireless networks. New networks will offer even greater speeds, equivalent to DSL and beyond.

These faster networks mean that Internet services formerly available only on desktop PCs are becoming available anywhere, in the palm of your hand, as a result of digital wireless technology.

Found Lower Purchase Price Elsewhere? Buy it at the best price here! Simply email and/or fax, Lowest Price Guarantee form if you find accessories or related supplies for less and await our response during business hours with a new lower cost of upto US $10 less. Competing retail suppliers or online stores must be located in USA or Canada. See product supply price guarantee form for details.