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iPhone?? Yes It is..
In January 2007, Steve Jobs introduced the Apple iPhone during his keynote address at the Macworld Conference and Expo. In its first appearance onscreen and in Jobs’s hand, the phone looked like a sleek but inanimate black rectangle.
Then, Jobs touched the screen. Suddenly, the featureless rectangle became an interactive surface. Jobs placed a fingertip on an on-screen arrow and slid it from left to right. When his finger moved, the arrow moved with it, unlocking the phone. To some people, this interaction between a human finger and an on-screen image — and its effect on the iPhone’s behavior — was more amazing than all of its other features combined.
And those features are plentiful. In some ways, the iPhone is more like a palmtop computer than a cellular phone. As with many smartphones, you can use it to make and receive calls, watch movies, listen to music, browse the Web, and send and receive e-mail and text messages. You can also take pictures and video (using an iPhone 3GS) with a built-in camera, import photos from your computer and organize them all using the iPhone’s software.
In 2008, Apple introduced the second generation iPhone. This iPhone can operate on third-generation (3G) cellular networks and has a GPS receiver. The iPhone also lets you view map and satellite data from Google Maps, including overlays of nearby businesses. Owners of the original iPhone got the opportunity to upgrade the software on their phones. The 2.0 software gives the old phones new functions, but without the GPS receiver or 3G network capability.
In 2009, Apple launched the iPhone 3GS. The newest iPhone models have more storage capacity than earlier iPhones. They also have a better camera that’s capable of taking still shots and video at 30 frames per second. Another new feature is a compass, which comes in handy when you need to find your way through unfamiliar territory. Also in 2009 came iPhone OS 3.0, which offered many improvements, such as the ability to cut and paste.
A modifie d version of the Macintosh OS X operating system used on Apple desktop and laptop computers lets you interact with all of these applications. It displays icons for each application on the iPhone’s screen. It also manages battery power and system security. The operating system synchs the phone with your computer, a process that requires a dock much like the one used to synch an iPod. It also lets you multitask and move through multiple open applications, just like you can on a laptop or desktop computer.
In January 2007, Steve Jobs introduced the Apple iPhone during his keynote address at the Macworld Conference and Expo. In its first appearance onscreen and in Jobs’s hand, the phone looked like a sleek but inanimate black rectangle.
Then, Jobs touched the screen. Suddenly, the featureless rectangle became an interactive surface. Jobs placed a fingertip on an on-screen arrow and slid it from left to right. When his finger moved, the arrow moved with it, unlocking the phone. To some people, this interaction between a human finger and an on-screen image — and its effect on the iPhone’s behavior — was more amazing than all of its other features combined.
And those features are plentiful. In some ways, the iPhone is more like a palmtop computer than a cellular phone. As with many smartphones, you can use it to make and receive calls, watch movies, listen to music, browse the Web, and send and receive e-mail and text messages. You can also take pictures and video (using an iPhone 3GS) with a built-in camera, import photos from your computer and organize them all using the iPhone’s software.
In 2008, Apple introduced the second generation iPhone. This iPhone can operate on third-generation (3G) cellular networks and has a GPS receiver. The iPhone also lets you view map and satellite data from Google Maps, including overlays of nearby businesses. Owners of the original iPhone got the opportunity to upgrade the software on their phones. The 2.0 software gives the old phones new functions, but without the GPS receiver or 3G network capability.
In 2009, Apple launched the iPhone 3GS. The newest iPhone models have more storage capacity than earlier iPhones. They also have a better camera that’s capable of taking still shots and video at 30 frames per second. Another new feature is a compass, which comes in handy when you need to find your way through unfamiliar territory. Also in 2009 came iPhone OS 3.0, which offered many improvements, such as the ability to cut and paste.
A modifie d version of the Macintosh OS X operating system used on Apple desktop and laptop computers lets you interact with all of these applications. It displays icons for each application on the iPhone’s screen. It also manages battery power and system security. The operating system synchs the phone with your computer, a process that requires a dock much like the one used to synch an iPod. It also lets you multitask and move through multiple open applications, just like you can on a laptop or desktop computer.
Let’s Know What is Smartphone
Think of a daily task, any daily task, and it’s likely there’s a specialized, pocket-sized device designed to help you accomplish it. You can get a separate, tiny and powerful machine to make phone calls, keep your calendar and address book, entertain you, play your music, give directions, take pictures, check your e-mail, and do countless other things. But how many pockets do you have? Handheld devices become as clunky as a room-sized supercomputer when you have to carry four of them around with you every day.
A smartphone is one device that can take care of all of your handheld computing and communication needs in a single, small package. It’s not so much a distinct class of products as it is a different set of standards for cell phones to live up to. This article explores what makes a cell phone a smartphone, how the idea came about and what you can do with it.
Unlike many traditional cell phones, smartphones allow individual users to install, configure and run applications of their choosing. A smartphone offers the ability to conform the device to your particular way of doing things. Most standard cell-phone software offers only limited choices for re-configuration, forcing you to adapt to the way it’s set up. On a standard phone, whether or not you like the built-in calendar application, you are stuck with it except for a few minor tweaks. If that phone were a smartphone, you could install any compatible calendar application you like.
Since cell phones and PDAs are the most common handheld devices today, a smartphone is usually either a phone with added PDA capabilities or a PDA with added phone capabilities. Here’s a list of some of the things smartphones can do:
- Send and receive mobile phone calls – some smartphones are also WiFi capable
- Personal Information Management (PIM) including notes, calendar and to-do list
- Communication with laptop or desktop computers
- Data synchronization with applications like Microsoft Outlook and Apple’s iCal calendar programs
- Instant messaging
- Applications such as word processing programs or video games
- Play audio and video files in some standard formats
Future applications promise to be even more impressive. For example, the Nokia 6131 is a phone utilizing near field communication (NFC) to allow the phone to act as a wireless credit card. The phone uses a two-way communication system to transfer payment information to pads at certain retail stores. Currently, it’s still in the trial phase of development.
Let’s Know About 3G
3G stands for “third generation” — this makes analog cellular technology generation one and digital/PCS generation two. 3G technology is intended for the true multimedia cell phone — typically called smartphones — and features increased bandwidth and transfer rates to accommodate Web-based applications and phone-based audio and video files.
3G comprises several cellular access technologies. The three most common ones as of 2005 are:
- CDMA2000 – based on 2G Code Division Multiple Access (see Cellular Access Technologies)
- WCDMA (UMTS) – Wideband Code Division Multiple Access
- TD-SCDMA – Time-division Synchronous Code-division Multiple Access
3G networks have potential transfer speeds of up to 3 Mbps (about 15 seconds to download a 3-minute MP3 song). For comparison, the fastest 2G phones can achieve up to 144Kbps (about 8 minutes to download a 3-minute song). 3G’s high data rates are ideal for downloading information from the Internet and sending and receiving large, multimedia files. 3G phones are like mini-laptops and can accommodate broadband applications like video conferencing, receiving streaming video from the Web, sending and receiving faxes and instantly downloading e-mail messages with attachments.
Let’s Know Cell Phone Network Technologies: 2G (Part 2)
TDMA
TDMA is the access method used by the Electronics Industry Alliance and the Telecommunications Industry Association for Interim Standard 54 (IS-54) and Interim Standard 136 (IS-136). Using TDMA, a narrow band that is 30 kHz wide and 6.7 milliseconds long is split time-wise into three time slots.
Narrow band means “channels” in the traditional sense. Each conversation gets the radio for one-third of the time. This is possible because voice data that has been converted to digital information is compressed so that it takes up significantly less transmission space. Therefore, TDMA has three times the capacity of an analog system using the same number of channels. TDMA systems operate in either the 800-MHz (IS-54) or 1900-MHz (IS-136) frequency bands.
GSM
TDM A is also used as the access technology for Global System for Mobile communications (GSM). However, GSM implements TDMA in a somewhat different and incompatible way from IS-136. Think of GSM and IS-136 as two different operating systems that work on the same processor, like Windows and Linux both working on an Intel Pentium III. GSM systems use encryption to make phone calls more secure. GSM operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the 850-MHz and 1900-MHz (sometimes referred to as 1.9-GHz) band in the United States. It is used in digital cellular and PCS-based systems. GSM is also the basis for Integrated Digital Enhanced Network (IDEN), a popular system introduced by Motorola and used by Nextel.
GSM is the international standard in Europe, Australia and much of Asia and Africa. In covered areas, cell-phone users can buy one phone that will work anywhere where the standard is supported. To connect to the specific service providers in these different countries, GSM users simply switch subscriber identification module (SIM) cards. SIM cards are small removable disks that slip in and out of GSM cell phones. They store all the connection data and identification numbers you need to access a particular wireless service provider.
Unfortunately, the 850MHz/1900-MHz GSM phones used in the United States are not compatible with the international system. If you live in the United States and need to have cell-phone access when you’re overseas, you can either buy a tri-band or quad-band GSM phone and use it both at home and when traveling or just buy a GSM 900MHz/1800MHz cell phone for traveling. You can get 900MHz/1800MHz GSM phones from Planet Omni, an online electronics firm based in California. They offer a wide selection of Nokia, Motorola and Ericsson GSM phones. They don’t sell international SIM cards, however. You can pick up prepaid SIM cards for a wide range of countries at Telestial.com.
CDMA
CDMA takes an entirely different approach from TDMA. CDMA, after digitizing data, spreads it out over the entire available bandwidth. Multiple calls are overlaid on each other on the channel, with each assigned a unique sequence code. CDMA is a form of spread spectrum, which simply means that data is sent in small pieces over a number of the discrete frequencies available for use at any time in the specified range.
All of the users transmit in the same wide-band chunk of spectrum. Each user’s signal is spread over the entire bandwidth by a unique spreading code. At the receiver, that same unique code is used to recover the signal. Because CDMA systems need to put an accurate time-stamp on each piece of a signal, it references the GPS system for this information. Between eight and 10 separate calls can be carried in the same channel space as one analog AMPS call. CDMA technology is the basis for Interim Standard 95 (IS-95) and operates in both the 800-MHz and 1900-MHz frequency bands.
Ideally, TDMA and CDMA are transparent to each other. In practice, high-power CDMA signals raise the noise floor for TDMA receivers, and high-power TDMA signals can cause overloading and jamming of CDMA receivers.
2G is a cell phone network protocol. Click here to learn about network protocols for Smartphones.
Now let’s look at the distinction between multiple-band and multiple-mode technologies.
Let’s Know Cell Phone Network Technologies: 2G (Part 1)
There are 3 common technologies used by 2G cell-phone networks for transmitting information (we’ll discuss 3G technologies in the next article):
- Frequency division multiple access (FDMA)
- Time division multiple access (TDMA)
- Code division multiple access (CDMA)
Although these technologies sound very intimidating, you can get a good sense of how they work just by breaking down the title of each one.
The first word tells you what the access method is. The second word, division, lets you know that it splits calls based on that access method.
- FDMA puts each call on a separate frequency.
- TDMA assigns each call a certain portion of time on a designated frequency.
- CDMA gives a unique code to each call and spreads it over the available frequencies.
The last part of each name is multiple access. This simply means that more than one user can utilize each cell.
FDMA
FDMA separates the spectrum into distinct voice channels by splitting it into uniform chunks of bandwidth. To better understand FDMA, think of radio stations: Each station sends its signal at a different frequency within the available band. FDMA is used mainly for analog transmission. While it is certainly capable of carrying digital information, FDMA is not considered to be an efficient method for digital transmission.
(to be continued)