Mobile phones can be divided into two categories: feature phones, which offer basic phone functionality and simple features such as Java games; and smartphones, which are in essence handheld call-making computers with internet access.

When choosing a smartphone, the choice of platform can be as important as the hardware specifications of the handset (see 'Platform', below). Like desktop PCs, the choice of platform will dictate ease of use, security, and choice of applications – ‘apps’ – that will be available for the phone.

Wireless connectivity: all phones have elementary wireless connectivity, if only for voice calls and SMS. For usable wireless data connections you’ll need at least EDGE (‘2.5G’) technology. But most wireless data today relies on 3G technology.

Confusingly, 3G data standards can be labelled UMTS, HSDPA, HSUPA; the latter two variants are sometimes known together as HSPA.

In urban Britain, you can expect 3G to provide at least 1Mb/s download connectivity, which is sufficient for easy web browsing. Beware of claims for 7Mb/s or 14Mb/s downloads - you’ll be lucky to see 5Mb/s under even ideal conditions, whatever the technology or commercial network.

Wi-Fi connectivity is ubiquitous in smartphones, all to 802.11b/g standard; many now to 11n specification.

Bluetooth was developed for mobile phones, and is useful for, for example, connecting a hands-free earpiece. Look out for the A2DP version of Bluetooth which allows stereo audio and better quality sound than with older Bluetooth connections.

The latest Bluetooth is v3.0 but most devices still get by fine with v2.0 or v2.1, often accompanied by Enhanced Data Rate (EDR) technology.

Display: since the original Apple iPhone, most smartphones now rely on capacitive touch-screen technology, with virtual buttons to press in place of real keys.

Older resistive technology is still found on the cheapest handsets but best avoided – it requires more pressure to activate and often mandates a stylus. Most phones now use capacitive touchscreen tech, and the best have multi-touch control, with natural gestures such as swiping and pinch-to-zoom facilitating simple control.

When looking for a smartphone, aim for a high resolution display to reduce pixellation of on-screen text – 320 x 480 can be considered a minimum for a 3.5in display, for example.

Instead of traditional LCD screen technology, some phones use AMOLED displays which offer more saturated colour but can be less easy to view in sunlight.

Battery life: like early ’90s GSM phones that barely lasted one day on a single charge, smartphone battery life is still short. The better smartphones now run two days or more between charges with intermittent calls and data use, and up to a week in standby.

Processor: all smartphones regardless of brand or platform use a processor licensed from British company ARM Holdings. These ARM chips take many forms, with clock speeds from around 400MHz to 1GHz, and are predominantly single-core designs. Memory helps keep the phone faster; expect upwards of 256MB.

Like a PC, backing up this processor will be a graphics processor to render on-screen animations and power games and video playback.

Storage: some smartphones are built with plenty of NAND flash storage on-board; others expect you to use a card such as microSD to store your media and other files. If you’re going to use your phone for music or video playback, you’ll need at least 8GB storage.

Camera: every self-respecting smartphone has a stills camera, and it’s usually enabled for video recording as well.

Many phones now have two cameras: front-facing for video calling, and rear-facing for photography/filming. Some webchat apps also allow switching to the rear-facing camera mid-call, so you can show your partner what you are viewing. Expect upwards of 3 megapixel resolution. Beware that number of megapixels provides little indication of quality of photos or video clips.

Other sensors: most smartphones now include many other sensors to assist their operation. Thse include a digital compass, global positioning system (GPS) radio, both to aid navigation. A light sensor helps adjust screen brightness to match environment.

An accelerometer/motion sensor and gyroscope have many uses, include auto-adjustment of screen orientation to suit how the phone is held, as well as assist in games and other apps. A proximity sensor is often fitted so that the screen is dimmed and deactivated when the phone is held to the ear to make phone calls.

Platform: early smartphones relied on Windows Mobile operating system, but the platform proved unreliable and difficult to operate. Microsoft stopped development of Windows Mobile at version 6.5 in 2009. Microsoft is now developing Windows Phone 7.

Aside from Windows Phone, in its infancy and with reduced developer or user following compared to other platforms, there are three smartphone operating systems on the worldwide market.

See all: Windows phones reviews

RIM'a BlackBerry OS was developed for business users, and was the first platform to facilitate email on a mobile phone. Even now it has a strong following in large business enterprises, who prize it for its security and ability to be locked-down by a system administrator.

See all: BlackBerry phones reviews

Apple iOS has the reputation as the most user-friendly and accessible operating system. It is currently used on Apple iPhone 3GS, Apple iPhone 4, iPod touch, iPad and iPad 2.

This OS has good security against malware and viral threats, due in part to the way all apps are screened by Apple before they are made available through the App Store. It is also the easiest to update with new upgrades.

See all: Apple iPhones reviews

Google Android is seen as a more ‘open’ platform since it was originally based on open-source Linux. Like Microsoft Windows, it can be installed on a wide variety of hardware; like Windows, it is also the platform most threatened by real malware. Beware that upgrades to Android are not always offered by the phone handset maker after releaed by Google; for example, many handsets sold with Android 1.6 or 2.0 will never be upgradeable to the current latest 2.2 or 2.3 versions.

See all: Google Android phones reviews