Buying guide: Cell phones

How does a mobile phone work?

A mobile phone allows you to communicate with other users via the transmission of electromagnetic waves between itself and base stations. A radio or a walkie-talkie works on the half-duplex principle, where signals are transmitted across a single frequency permitting only a one-way communication at a time. Mobile phones, on the other hand, use full-duplex technology that allows signals to be transmitted across two distinct frequencies enabling a simultaneous two-way communication.

The transceiver of most mobile phones has a limited range when it comes to coverage area. To enable continuous signal reception, a large area is divided into hexagonal cells, with each cell having a base station. These cells, together, manage to cover an entire city. Today, the whole world is connected by a very complex and dense cell arrangement. Owing to this system, even during travelling long distances, a mobile phone seamlessly migrates from one cell to another. When the user is moving from a cell towards another, the other cell picks up the signal from the user’s mobile phone and so on. This is how a mobile phone user is “always reachable” no matter where he/she is travelling.

Benefits of mobile phones 

The palm-sized mobile phone has become an indispensible gadget for personal and business communication. Initially the primary use of a mobile phone was limited to making calls and sending SMS. An entry level mobile phone provides these functions:

• Call waiting and call divert
• Auto and manual network selection
• Speed dialing and auto redial
• A phone log showing missed, received and dialed calls
• A phone diary to store contact details
• A message log showing sent, received and delivered SMS
• A calculator, a calendar with reminder facility
• A notepad for making a to-do list
• An alarm device
• FM radio

With rapid technological advancement, a whole gamut of features has been introduced that has taken the basic handset to unprecedented levels in terms of functionality. The latest mobile phone has become a digital multimedia tool, a mini-PC, a personal organizer and a lot more.

In its humble multimedia avatar, the modest mobile phone comes with a built-in MP3 player, a digicam, a video-cam and a gaming device. The number of pictures, videos, and other data that can be stored depends largely on the phone’s storage capacity. Along with a basic internal memory the latest mobile phones provide slots for inserting memory cards of varying types and capacities for additional storage.

With built-in GPRS, the mobile phone connects to the internet to enable net browsing, sending and receiving emails, downloading ringtones and wallpapers. It also uploads and downloads pictures, audios and videos to share with friends and family. An internet enabled mobile phone also allows the user to connect to social networking sites such as Facebook and Twitter. Nokia has some very good options when it comes to multimedia mobile phones. For hardcore game aficionados, the modern day mobile phones offers a whole vista of single and multi-user games devised exclusively for mobile phones. Whereas USB connectivity allows mobile phones to connect to PCs or Laptops for sharing information.

Besides these, another addition to the modern day mobile phone family is the intelligent mobile phone, popularly known as the Smartphone. Most Blackberry mobile phones and iPhones are fine examples of smart phones. Smartphone combines the functionalities of a wireless, internet-enabled PC and a PDA (personal digital assistant) in a single handset, making it a powerful business tool. The PDA features allows people to the flexibility to conduct business while on the move. Taking notes, reviewing spreadsheets, making and editing appointments, documents and contacts is possible in a snap. The Smartphone also include an electronic diary that allows for an unlimited contact list, sends automatic reminders and keeps you updated with the latest happenings around the world. A GPS-enabled Smartphone is able to show the user’s exact location, provide round-the-clock access to maps and directions, give traffic alerts, weather reports, and provide news coverage as well. The Smartphone is also a marketing tool thanks to its ability to send MMS clips that lets you include animation, graphics and music in a message.

Purchasing criteria 

Below listed are some parameters that you need to keep in kind when buying a new mobile phone. These parameters are designed to assist you in buying a mobile phone that meets your expectations.

Radiation levels: While the mobile phone offers many benefits to the user, it also spells trouble if used excessively. As mobile phone work on electromagnetic waves, one is always at a risk of getting exposed to excess radiation that can have detrimental effects on the health ranging from brain tumors to impotency. Taking the famous adage ‘Heath is wealth’ into account, the health authorities have specified a limit of radiation exposure safe for humans. It is now mandatory for mobile phones to have a Specific Absorption Rate (SAR) certification. A mobile phone’s radiation emission should be way below this specified safety limit.

Network compatibility: GSM and CDMA are the two major network technologies supported by most service providers. A GSM mobile phone will not work with a service carrier that operates on CDMA technology and vice versa. Be sure to check whether the mobile phone that you intend to buy supports the network you want to use. Many of the service providers offer attractive mobile phones with their service packages. Verizon mobile phones, Alltel mobile phones, AT&T mobile phones, Sprint mobile phones, and T-mobile mobile phones are some prominent options. Also note, unlocked mobile phones are also available; these phones can be used across different service providers.

Multimedia Capabilities: From simple ring tones to alarm function to calendar, today, the mobile phone has progressed to offering a vast range of advanced multimedia capabilities. High-end media player, radio, digital camera, large display screen with playback support for multiple format images and videos, polyphonic ringtones, to-do list-making, word document/PDF reader, and high-end graphics that supports gaming are some of the multimedia features that a current generation mobile phone offers. Check the specifications for the supported functionalities before you make a purchase.

Internet Capabilities: The current generation mobile phones are almost like palm-sized computers as they provide you the facility to stay connected and access your files, your network and do a lot more via supported internet capabilities, just like a computer. Along with the usual SMS, MMS and instant messaging, features to check out in any mobile phone for internet-specific usage include browser type, email support, chat support and media downloading support.

Push To Talk (PTT): This feature lets you use your phone like a walkie-talkie whereby you can instantly connect with anyone you want to. This feature allows the user to communicate within a group with many people at the same time.

Phone memory and external memory upgradation: Every mobile phone comes with a basic internal memory that allows it to save contact details in your address book, download Internet files, save photos and movie clips, store ringtones and MP3 files. Higher resolution images create a larger file that occupies more memory. If you intend to save lots of data on your mobile phone, look for a mobile phone that has large internal memory along with support for memory cards for memory expansion. Memory cards, today, come in different varieties and with different storage capacities right from 128 MB, 256 MB, 512 MB, and 1 GB, 2GB, 4GB and more. Check for the maximum expandable memory supported by your mobile phone.

Display: Nowadays most mobile phones come with a color LCD display. However, the display quality depends on the resolution that is represented as the number of pixels per inch, and color depth which is the number of colors that can be displayed. Higher values translate into a better display. Mobile phones offering basic features can have a monochrome screen as well.

Touch screen: A Touchscreen allows navigation by touching the screen or icons on the screen by an accompanying stylus or by finger. Touchscreen phones are expensive but are interactive, stylish, trendy and fun to use.

Infrared and Bluetooth Connectivity: Mobile phones offer two types of wireless connectivity that allows the user to share data between two or more mobile phones. Bluetooth also allows user to connect their mobile phones with laptops that are Bluetooth-enabled.

USB port: A USB port connects the mobile phone with the PC to facilitate data transfer between the two devices.

Camera: New phones offer state-of-the-art digital cameras ranging from 1 Megapixel onwards. Higher the camera resolution sharper the images or movie clips. Most of the mobile phone brands offer models with good camera capabilities; in fact, Nokia mobile phones are available in plenty of camera-oriented models featuring high-end cameras.

Battery: Most mobile phones come with Lithium-Ion batteries with greater energy storage capacities. Look for phones that have batteries offering greater standby times and talk times.

Summary 

• Mobile phone, or mobile phone, as many of us call it, has revolutionized the way we communicate, allowing us to do a lot more than just talk. This versatile wireless electronic communication device lets us talk, send messages, pictures, and videos, conduct conferences, and network with anyone from anywhere across the globe.
• Mobile phones communicate via electromagnetic radio waves. Signal transmitters located in base stations across the globe consist of a wireless antenna that sends and receives radio signals.
• Be sure to check whether the mobile phone that you intend to buy supports the network you want to use. Many of the service providers offer attractive mobile phones with their service packages. Verizon mobile phones, Alltel mobile phones, AT&T mobile phones, Sprint mobile phones, and T-mobile mobile phones are some prominent options. Also note, unlocked mobile phones are also available; these phones can be used across different service providers.
• As users move from one location to another, the mobile phone communicates with different base stations which may be operated by different mobile operators.

Nokia has some very good multimedia mobile phones while iPhones and Blackberry offer high-end smartphones.

Making a decision 

Depending upon your actual needs, make a list of all the features that you want in your mobile phone. Make an intelligent choice after comparing various handset models across the range that falls within your budget. Before zooming in on a particular mobile phone, check out the model specifications. An important feature to consider is the after-sales service and the manufacturer’s warranty.