http://www.freecellphoneswithcontract.com/cell-phone-att-htc/
Working of Cell Phones
Cell phones or cellular phones are so called as they cover compartmentalized, cell like areas. The origin of the Cell phone can be traced back to the year 1973 when Motorola came up with World`s first cellular portable telephone which was commercialised as Motorola DynaTAC 8000X.
These days, new cell phones are being added at a rapid pace. The parts of them typically consist of following: circuit board; antenna; keyboard; LCD – liquid crystal display; battery; microphone; speaker.
In recent times, they are available with a wide range of functions. To list a few functions, depending on the type of cell phone you choose: store contact information; keep track of appointments; set reminders; prepare to-do lists; send/receive e-mail; play games; send text messages (sms); access to internet; watch and enjoy TV; built-in calculator; integration with other devices like GPS receivers, MP3 players, etc.
Cell phones, operating on radio frequency, have come up with an innovative cellular approach to counter limited availability of RF spectrum. Now, several cell phone towers are used to cater to a large geographic area.
Each tower (base station), covers a circular area called a cell. A large region is split into a number of cells allowing different base stations to use the same channels/frequencies for communication. This enables thousands and thousands of mobile telephone users to share far fewer channels.
Another important aspect is that, phones need less power to transmit to reach any base station as each base station covers a smaller area. Reducing the required transmit power reduces the size of the battery and thereby the weight of the phone. This has led to miniaturization of cell phones which would not have been possible without the cellular technology.
When you use your cell phone, following things happen. First the phone locates base station having strongest signal, and requests for a channel assignment. The base station permits channel assignment and the call gets accepted. The call is then forwarded to the local telephone network if it is to a regular phone otherwise it is transmitted through the cellular network. The call is then sent to its destination through the telephone network.
When the cell phone is switched on, SID (System Identification Code) on the control channel compares it to the SID programmed into the phone. If the SIDs match, the phone understands that the cell is communicating with home system. The phone sends a registration request, along with the SID and the MTSO keeps track of the phone`s location in a database. If the SID on the control channel does not match the SID of your phone, then the phone is in roaming.
The three technologies commonly used by 2G cell phone networks for transmitting information: frequency division multiple access (FDMA); time division multiple access (TDMA); code division multiple access (CDMA).
GSM (Global System for Mobile communications) implements TDMA, to connect to the specific service providers in different countries. GSM uses subscriber identification module (SIM). SIM stores all the connection data/identification numbers needed to access a particular wireless service provider.
Standard 2.5G protocols used widely are GPRS, EDGE to name a few. Some latest 3G protocols are: Universal Mobile Telecommunication Service (UMTS); Wideband Code-Division Multiple Access (WCDMA); High-Speed Downlink Packet Access (HSDPA); Evolution Data Maximized (EVDO).
A few popular cell phone models in the market have been offered by Nokia, Ericsson, Motorola, Samsung, LG, etc. with each model with its own range of collections.The year 2008 may be a high watermark in the cell phone history with Nokia N-Gage 2, HTC Dream, Apple iPhone 2, BlackBerry Touchscreen, Sony PlayStation Phone which are expected to be launched.
About the Author
This article can be accessed in portuguese from the Article section of page www.polomercantil.com.br/celular.php
Roberto Sedycias works as IT consultant for www.PoloMercantil.com.br
AT&T Pure (HTC) Windows Mobile 6.5 Phone – Unboxing
|
|
(10 Items Combo) Tool Repair Kit Precision Screw Driver Set Torx + Flat Head + Safe Plying Prying Pry Tool for Motorola Verizon Sprint Att Cingular Razr Razorand More $10.90 Item 1 – 7 : Magnetized tips precision torx screw driver. Sizes : T3, T4, T5, T6, T7, T8, T10. Durable with precision cut sizes to ensure you can get the job right like a professional. Support end (blue color ends) give you the ability to turn the screw driver and holding it still, and magnetized tips to hold the screws to avoid dropping the tiny parts. Use this kit to repair cell phones, laptops,… |
|
|
Universal Generation X Cell Phone Antenna Booster Signal Enhancer for Htc cell phone $0.01 Universal Generation X Cell Phone Antenna Booster Signal Enhancer for Htc cell phone . The Universal Generation X Cell Phone Antenna Booster Signal Enhancer is a passive device designed to capture stray radiation in the body of the cell phone and to re-radiate the signal to improve the phones reception. The signal booster will work most efficiently when installed properly. When using the phone, tr… |
|
|
HTC HTC2000 Universal Mobile Base $64.50 If you’re like us, you’ve crammed more tools into your workshop than can really fit. Luckily, an HTC universal mobile base (or two) can make a world of difference. The base is sturdy and easy to assemble, plus–unlike any other mobile base on the market–it adjusts to fit virtually any large woodworking machine, forming squares from 12 by 12 to 36 by 36 inches and rectangles as big as 20 by 52 inc… |
|
|
Duracell Mygrid Usb Charger $10.95 Duracell myGrid USB ChargerDuracell myGrid USB charger is portable power that charges 100′s of devices on the go.It’s Charging Made Simple.Charges 100′s of DevicesCompatible with Apple USB Cable4+ hours of Talk Time for iPhone and BlackBerry… |
|
|
ARTISTRY TIME DEFIANCE Lifting Eye Crème .53 fl. oz. $25.00 Solve your eye area problems with one powerful anti-aging eye creme. Hydrate, restore, and defend skin with the exclusive Derma Cell Exchange technology to help your skin “remember” how to be young again. TIME DEFIANCE® Lifting Eye Creme is the at-home alternative to an eyelift.*… |
|
|
Duracell myGrid $121.41 With Duracell myGrid you can charge up to 4 devices at one time. Just place your myGrid enabled devices anywhere on myGrid’s surface and they start charging – It’s Charging Made Simple…. |
|
|
Sandisk 4GB MicroSDHC Memory Card with SD Adapter (BULK Packaging) $0.01 Not all devices support microSDHC 4.0GB cards. Some devices support SD HC but NOT 4 GB in size, but only 2 GB. PLEASE CHECK BEFORE BUYING Please contact your device manufacturer for details. To ensure compatibility, look for the microSDHC logo on the product or packaging of your new phone or PDA. We CANNOT replace cards once they have been inserted into a device. Please make sure that your devices… |
|
|
Griffin Powerjolt Dual Universal USB Micro $0.01 For MP3 players and other devices that get their power through USB. Plug your device’s USB cable in and charge from almost any vehicle’s 12 volt accessory outlet with this low-profile, micro form-factor PowerJolt. A built-in resetting SmartFuse protects against voltage spikes, with no blown fuses to replace…. |
|
|
Transcend 32 GB microSDHC Flash Memory Card TS32GUSDHC4E [Amazon Frustration-Free Packaging] $19.99 SDHC Class 4 and SD 2.0 compliant, a speed of 4MB/s is guaranteed… |
|
|
Motorola Vehicle Power Adapter micro-USB Rapid Rate Charger $29.99 Motorola SPN5400A microUSB Car Charger… |