Some Important Cell Phone term definition

Confused by the alphabet soup of cell phone acronyms? I don't blame you. Here's a cheat sheet that'll help you navigate the waters while your shopping for your next phone—or trying to get the most out of the handset you've got.Most of the confusion arises when it comes to the various types of cell phone networks. For example, when I ask my aunts and uncles which networks their phones work on, they'll usually tell me their carrier instead of whether they're using GSM or CDMA—and frankly, before I started writing about cell phones for a living, I didn't know the difference, either. So first, let's start with a quick overview of the two main standard for cell networks:

GSM: Short for Global System for Mobile Communications, GSM is the most widespread standard for cell phones networks in the world. If you're a jetsetter who likes keeping in touch during your far-flung travels, you should go with a GSM-enabled phone. The main distinction of a GSM phone is that it comes with a SIM (Subscriber Identity Module) card—a little plastic chip that, as its name implies, identifies your phone on the GSM network. If you take the SIM card out of your GSM phone and put it into another GSM handset, you'll be able to place and receive calls on the second phone using your own cell phone number. GSM phones are also capable of handling six-way conference calls.

CDMA: Short for Code Division Multiple Access, CDMA networks are much more prevalent in the U.S. than they are abroad, and while CDMA boasts many of the same features as GSM networks (including caller ID, call waiting, and text messaging), there are some key differences—namely, CDMA phones don't use SIM cards. Instead, your phone's identity and number are programmed into the handset by your carrier, and you can't easily switch numbers on CDMA phones as you can with SIM-equipped GSM phones. Also, CDMA phones can only handle three-way conference calls, versus six-way calls on GSM networks.

OK, so you've got your two main flavors of networks, but now I'm going to stir another variable into the mix: 3G. Here's the deal: GSM and CDMA are both considered second-generation, or 2G, networks (the first generation being AMPS, an analog network used mainly back in the 1980s). Unlike the old voice-only AMPS networks, digital GSM and CDMA networks can handle both voice and data calls, which means you can send text messages, surf the Web and get caller ID info. But data flows slowly over GSM and CDMA—think dial-up, only slower. Streaming video and music? Forget it.

That's where 3G, or third-generation networks, come in. These so-called 3G systems allow data to flow at speeds you'd expect from a home DSL modem or better—and at those speeds, you get features like streaming video and full-track music downloads. The main types of 3G networks include:

EV-DO: An add-on for CDMA networks, EV-DO (or Evolution-Data Optimized) delivers data speeds between 144Kbps to 2Mbps to CDMA cell phones, perfect for streaming video and music. Sprint offers EV-DO access through its Power Vision phones (which are typically a little pricier than standard models); on Verizon Wireless, look for the "V Cast" label.

UMTS and HSDPA: Both UMTS (Universal Mobile Telecommunications System) and HSDPA (High-Speed Downlink Packet Access) are upgrades to GSM networks, and like EV-DO, they provide DSL and cable-like data speed. The only difference between UMTS and HSDPA (besides the technical nitty-gritty, of course) is that HSDPA is even faster than UMTS; for that reason, HSDPA networks are often called 3.5G rather than just 3G.

Somewhere between 3G and 2G lies, naturally enough, 2.5G networks, which give you data speeds that are slightly faster than dial-up—no good for streaming video, but fine for messaging or mobile Web browsing. These networks include:

1xRTT: A variant of the CDMA standard, 1xRTT (or "1 times Radio Transmission Technology") gives you data speeds between 30Kbps and 90Kbps, a bit better than your typical 56Kbps dial-up modem. Most of the non-3G phones on Sprint and Verizon have 1xRTT capabilities.

GPRS and EDGE: The 2.5G flavors of GSM networks, GPRS (General Packet Radio Service) and EDGE (Enhanced Data Rates for GSM Evolution) also give you data in the 30Kbps to 90Kbps range, with EDGE running slightly faster than GPRS. Again, most of the non-3G phones on AT&T offer either GPRS or EDGE, while T-Mobile—which has yet to launch a 3G network—only does GPRS and EDGE.

Some other terms are:

xHTML: eXtensible HyperText Markup Language

A newer version of the HTML markup language (code) used to create Internet web pages. Unlike the older HTML, xHTML includes several core features designed specifically with mobile devices in mind. Special versions of xHTML - such as xHTML Basic and xHTML Mobile Profile - are designed specifically for mobile devices. xHTML also includes features that allow a website designed for a full PC to automatically display in a simplified version on a mobile device. xHTML also adheres to strict XML rules, which makes it much easier for devices with limited processing power (like phones) to understand and display quickly and consistently. xHTML is a core part of the WAP 2.0 standard, replacing the WML language that was used in WAP 1.x.While most new phones support xHTML, many older phones only support WML and/or HDML.

XML: eXtensible Markup Language

A standard that forms the basis for most modern markup languages. XML is an extremely flexible format that only defines "ground rules" for other languages that define a format for structured data designed to be interpreted by software on devices. XML by itself is not a data format.Examples of XML-based standards include xHTML, for creating web pages, RSS, for feeds of new information (such as news headlines), and SyncML, for managing personal data such as contacts, email, files, and events.

WML: Wireless Markup Language

An industry-standard markup language for creating tiny web sites optimized for phones.WML was a core feature of the WAP 1.x standard.WML is being phased out in favor of the newer xHTML standard, part of WAP 2.0.Older phones may only support WML sites.

WLL: Wireless Local Loop

Wireless service systems that compete with or substitute for local wireline phone service.

WAP: Wireless Application Protocol

A technology designed to allow efficient transmission of optimized Internet content to cell phones.

VOICE MAIL: A service provided by a phone network to store and manage voice messages for individual users. Like an answering machine, voice mail can handle a call when the person being called is unavailable, by playing a greeting message and recording a voice message from the caller. From a modern mobile phone, the voice mail system can usually be accessed by pressing and holding the "1" key, although some phones use a different key, or require dialing a code. Once connected to the system, voice messages can be retrieved and managed using a traditional phone menu interface. Many voice mail systems also offer advanced options such as different greetings for different times or dates, or fax management.

VOICE DIALING: This lets you speak a name to dial a number instead of entering a number manually or choosing it from the phone book.There are two types: speaker-dependent (recorded) and speaker-independent (recognition).With speaker-dependent, voice dial entries must be explicitly created by speaking and recording the name 1-3 times. The phone will only respond to recorded names, and usually only when spoken by the same person who recorded them. The maximum number of voice dial entries is usually limited to a fraction of the size of the whole phone book.With speaker-independent voice recognition, no recording is required. The name can be spoken by anyone, and the phone will automatically match the spoken name with the closest name entered in the phone book.Speaker-dependent is the most common type, especially on older phones. If the type isn't specified, it is usually speaker-dependent.

VGA: Video Graphics Array

A standard size/resolution for digital cameras, images (files), and displays. VGA size is 640 pixels wide by 480 pixels tall (or vice-versa in portrait orientation). VGA is larger than CIF, QCIF, and QVGA, but smaller than megapixel.

SVGA: Super Video Graphics Array

A standard size/resolution for images (files), and displays. SVGA size is 800 pixels wide by 600 pixels tall (or vice-versa in portrait orientation). SVGA is larger than CIF, QVGA, and VGA, but smaller than 1 megapixel.

SYLUS: A small pen-like instrument used to "write" on a touch-screen device. A stylus is often nothing more than a simple stick of plastic, except that its tip is specifically designed to not damage the screen. The stylus provides far more accuracy than could be achieved with a fingertip, and provides a familiar pen-like experience for inputting handwriting or drawings.

SOFT KEYS: Soft Keys are multi-function keys that use part of the display to identify their function at any moment. Because of this, they are usually located directly underneath the display.

QUAD BAND: Designates a GSM phone that supports all four major GSM frequency bands, making it compatible with all major GSM networks worldwide. The four bands include the 850 and 1900 MHz bands - used in the Americas - and 900 / 1800, used in most other parts of the world. Compared to a tri-band phone supporting the 900 / 1800 / 1900 bands, a quad-band phone adds support for GSM 850 for full coverage in the Americas. Compared to a tri-band phone supporting the 850 / 1800 / 1900 bands, a quad-band phone adds support for GSM 900 for full coverage in Europe and Asia.

PIXEL: The smallest visual unit in an electronic display or visual data file; a single "dot". Most modern electronic displays are composed of a grid of pixels. Each pixel can be turned on or off, or - in the case of full-color displays - dimmed or made a specific color. In this way, pixels are individually controlled to cause the whole display to show information and graphics. An important measure of an electronic display the number of pixels. More pixels allow the display to show more detail and more information. This is called "resolution", and is typically stated in terms of vertical and horizontal pixels (such as 240 x 320). Pixels can also be used to describe the smallest visual unit in a visual data file, such as a captured photograph or video clip.

MEMORY CARD SLOT: Memory card slots are used primarily to add memory to a phone, in the form of a memory card. Extra memory can be used to store and transfer photos, videos, music, computer files, or backups of phone data such as the phone book and calendar. Some card slots also support cards with other functions, such as Wi-Fi connectivity or an NFC reader. In this way the card slot can be used to add features to a device. The most common standard for this capability is SDIO, which we list as a separate feature. There are several different types of cards. Each has a different shape and size, but cards from a phone can also be used with other devices which use the same type of card. Such devices might include handhelds, digital cameras, and MP3 music players.

BROWSER: In wireless phones, built-in software that allows the user to access special Internet sites using their phone. While nearly all browsers in phones can view sites made especially for phones, only some can also display "full" web sites.

BLUETOOTH: Bluetooth is a short-range wireless technology used to create PANs (Personal Area Networks) among your devices, and with other nearby devices.Bluetooth allows you to leave your phone in your pocket, while talking on your phone with a Bluetooth headset - with no wires. You can also exchange contact or scheduling information with other Bluetooth-enabled phones nearby, or send such information to a nearby Bluetooth-enabled printer.Another common use is to give your laptop computer or PDA wireless high-speed Internet access via Bluetooth and your phone. Many newer automobiles also have Bluetooth, which can interface with a phone in a pocket, to allow automatic hands-free phone capability. More innovative uses include playing a game against someone with a similar phone nearby, or using a special Bluetooth pen to send SMS messages by simply writing them on paper. Bluetooth functionality is divided into separate types of connections known as "profiles". Each of the various scenarios outlined above involve a different profile. Not all Bluetooth devices support all profiles. For example, most phones support the Headset (HSP) and Handsfree (HFP) profiles, for connecting the phones to headsets and car kits, respectively. But not all phones support the Object Exchange (OBEX) profiles, which let you transfer files (like photos) (FTP) and/or information (like contacts and events) (OPP) to and from other devices. Another profile supported by only some phones is Dial-Up Networking (DUN), which lets you connect a laptop or PDA to the Internet via the phone. Other optional profiles support connecting to printers (BPP), keyboards (HID), and stereo headphones (A2DP, AVRC).Most Bluetooth phones are "class 2", which means the Bluetooth feature has a range of up to 30 feet. Class 1 phones (which are rare) can have a range of up to 300 feet. Bluetooth is named for the 10th century Viking king Harald Bluetooth, who united Norway and Denmark.

AIRTIME: Time spent communicating using a mobile phone. The time is tracked by wireless carriers (service providers) to determine billing charges. Usage includes sending or receiving calls and other wireless transmission such as faxes, e-mail or data files. Most carriers charge for a whole minute even if only part of a minute is used.

Whew! That's a lot of terminology. I'll tackle more wireless acronyms in future posts; in the meantime, if you're curious about the technical details of the various cell networks, I'd suggest combing through Wikipedia.