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Every major mobile phone maker may be trying their hand at touchscreens in the wake of the iPhone, but with the KF600 LG has managed to come up with a touch-controlled phone offering something distinctly different.

To start with, LG hasn't opted for full, large screen touch operation, like Apple's iconic handset, and LG's own successful Viewty. Instead, it has introduced a novel twin screen hybrid arrangement on a sliderphone chassis.

LG's touchscreen masterpiece

Only one of the displays is touch-controlled - the lower of the two on the front panel - with the touchpad buttons changing context to suit whichever operation or function you're using at the time.

If you're in camera mode, the buttons on the lower 'InteractPad' touchpad assume camera button roles; in the music player, you get track control keys; and in normal menu navigation, you get navigation up/down, left/right arrows and select key options. Slip into media viewer mode or messaging choices, and the virtual buttons switch again to optimise usability.

The upper display on the LG KF600 is resolutely non-touch operated, and presents menus and options in a way that will be familiar to most conventional phone users.

Effectively, it feels like the LG KF600 is a kind of hybrid, combining touchpad operation with regular mobile navigation conventions. It certainly is an unusual and interesting design.

Beneath the idiosyncratic user interface, the KF600 has a fairly standard roster of mid-tier mobile features. It doesn't support 3G connectivity, let alone Wi-Fi, and isn't built on a smartphone operating system.

Its key features, besides the InteractPad system, are a 3-megapixel camera with autofocus and photo light, an MP3 player, an FM radio, video player and a range of organiser functionality.

An attractive and intuitive mobile phone

There is a familiarity about much of the InteractPad's changing buttonry that gives it a surprisingly intuitive feel soon after turning it on for the first time.

That's because the InteractPad, in many respects, replicates with its touchpad controls a conventional phone navigation pad's functionality. At least, enough to make it straightforward to operate for most mobile users coming at touch control fresh.

The dual-screen design sits the non-touch main 2-inch screen above the smaller 1.5-inch touch-sensitive screen. Both are QVGA (240x320 pixels) 262K-colour arrays. This gives theimpression of one large split front panel display, though in reality the important content viewing action happens only on the 2-inch display. That's not a huge amount of screen viewing space for a sliderphone measuring 101.2(h) x 50.7(w) x 14.1(d) mm.

It's quite an attractive design, with a smooth all black look and chrome trim. The slider numberpad is as smoothie too, slipping into place with a solid slide mechanism. Keys are large, although individual numbers aren't separated as well as we'd prefer on the glossy flush surface.

InteractPad action

The lower InteractPad touchsceen is the essential part of the KF600's control system. It offers haptic feedback - a slight vibrating buzz to let you know keys have been pressed - which eliminates much of the mis-pressing or have-you-haven't-you frustration you get on some non-haptic touchscreens.

The InteractPad approach can take a little getting used to, particularly if you've been recently exposed to other touchscreen devices.

To start with, our instinctive reaction was to tap the upper screen options as well as the lower InteractPad. This may be different for people who haven't 'touched' lately, and it's a response that soon wears off.

The InteractPad interface initially offers you a set of six quick access buttons to work from. You get messaging, phonebook, alarms and sound profiles, a main menu access button, and a button to switch off the quick access panel and lock the keypad.

If you do switch off the quick access keys on the InteractPad, both the KF600's displays interact, with animated wallpapers appearing to move across them. Interestingly, LG has included some striking themes based on Keith Haring's distinctive artwork, which provides a stunningly colourful set of screensavers that use the double screen to eye-catching effect.

Tapping the menu button opens up the InteractPad functionality properly. You initially see four directional arrow keys, an OK button and back option. This brings to mind the LG Chocolate phone's touch navigation pad, and the options mirror what you'd have on standard navigation pad.

User-friendly interface

The menu system on the main screen won't shock anyone - it's conventional stuff, with a menu grid (or list if you prefer), that you scroll around and press OK to select. Sub menus are listed by number, so you can scroll up or down, or simply press the corresponding number on the slider numberpad. All very straightforward.

As you progress through menu options, the InteractPad adapts to what you're doing, with buttons altering function depending on what options are available - much like how softkeys on regular phones alter as you go along, but in a graphically richer way.

Touchpad responsiveness isn't as quick as a standard navigation D-pad manual control, however, the InteractPad taking a moment after tapping to respond to your command. It's not horribly slow, but not as slickly responsive as the best (iPhone) touchscreen systems.

You can use your finger to swipe down lists such as phonebook entries, images or track lists, but with not much finger space you have to be careful what you're doing and it doesn't feel breezily easy.

A look at the music player

So what else does the InteractPad do other than replace the navigation pad? Fire up the camera or MP3 player and you get a better idea of what LG is up to. There's a fast access key for the MP3 player on the side, taking you in quickly to the system.

The music player is initially quite underwhelming. You're presented with a regular dull sub-menu with three options - songs, playlists and settings. It's only when you select a track to play that the interface transforms into something a bit more dynamic.

The main display has track details and album artwork, while the InteractPad changes its look with a large set of player control buttons, and a track progress bar you can slide back or forward to skip through a track.

It looks good, admittedly, for a mid tier phone. You can of course get these control functions on many regular phone navigation pads, without the slick graphics, but there is a user-friendly, quite stylish feel to it. Similarly, the FM radio interface has been well designed and is simple to operate.

Plays plenty of formats

The performance of the music player can be good, although the supplied headphones are distinctly average and don't play to the music player's strengths.

They are connected to the phone with an LG connector, but are a two-piece set, with a 3.5mm jack socket mid-line so you can plug in other headphones. This is strongly recommended to make the most of the music player's sound quality.

The KF600's multimedia player supports a variety of audio and video file formats including MP3, MPEG4, WAV, 3GP, AMR-NB, WMA, MIDI, AAC, AAC+, and eAAC+.

There's a limited 25MB of onboard storage capacity, though MicroSD card expansion is supported. Cards up to 2GB can be used with the phone, with a slot tucked away under the battery (you can't hot-swap cards).

An impressive camera

The camera similarly demonstrates the thinking behind the InteractPad context-changing interface. Press the dedicated camera button on the side and both displays swing into landscape mode, and the InteractPad buttons reconfigure for camera action.

You can use the side/top mounted camera button as a viewfinder or the InteractPad capture buttons. The pad also takes cares of adjusting the variety of settings you can tweak.

This appears to be practical and uncluttered, but can get fiddly in lighting conditions where you can't properly make out the InteractPad screen options. Real buttons could carry out the option select and scroll button functions just as effectively - if not better.

With a 3-megapixel camera onboard and autofocus, you can take some decent quality pictures with the LG KF600. A macro mode means you can get in close while shooting too. Images can be rich, colourful and detailed, particularly in well-lit situations and exposure is usually well handled.

The autofocus system does require a few extra moments to set the image before you capture it, and while this enables you to get better images, some users taking spontaneous snaps may find this frustrating.

And it's not the quickest camera around either - it takes a few moments after you've hit the capture button to take the picture, so you need to keep it steady while it's processing.

Some great image features

There is an anti-shake option alongside other tweaking features too. Rather than a flash though, the LG KF600 has an LED photo light that has to be switched on, offering some extra illumination but not the more powerful and effective extra lighting you'd get from Xenon flash.

The InteractPad has another trick up its sleeve when viewing captured images. You can zoom in to view part of the picture on the main screen, with a thumbnail of the whole picture shown on the InteractPad, allowing you to target the zoomed area and easily pan across the picture. You can also rotate and expand you own images to fill both screens as wallapapers.

The LG KF600 has a video recording capability, delivering a fairly average mobile shooting performance at maximum QVGA resolution.

Handwriting recognition

Although text messaging utilises the sliderphone's numberpad, LG does throw in a bit of extra touchscreen gadgetry. Handwriting recognition is an option for text and email, with the InteractPad allowing you to scrawl letters with your fingers.

Although you can write letters easily, the extra buttons surrounding the writing area are so tiny, it becomes fiddly to use it fully. Nice idea, but the 1.5-inch screen isn't really big enough to make it practical, we reckon - the numberpad is far easier for texts and emails.

A document viewer inside enables you to view email attachments, or standard format document files copied or loaded on to the phone. Other standard organiser features- such as voice memo recorder, calendar, memo notes, convertor and various chronology options - are included.

The browser on the LG KF600 is unexceptional, the sort you'd expect on a mid-level mobile, and you can access full web pages. But with no 3G to speed things along it can take time to render some pages.

LG has also preloaded the Yahoo! Go 2.0 mobile application, providing a widgets style base for getting regular information updates, news, web feeds, Yahoo! email, search, mapping information, and so on, all in one place.

Impressive battery life

As for voice calls, the LG KF600 put in a consistently strong performance - we got a pleasantly reliable quality level, with good all round sound quality.

Battery life is estimated by LG to be unexceptional for a non-3G phone- up to 300 hours in standby or up to 3 hours talktime. The twin-screen activity when operating functions probably doesn't help battery life.

In our tests, with average usage including a modest amount of music playing and camera snapping, we managed between two and three days between recharging. As usual, more intense use- or switching off the screensaver timer - will drop battery life accordingly, but it didn't demonstrate any notably power-hungry tendencies.

A match for the Viewty or iPhone?

Behind the interesting InteractPad user interface, LG KF600 offers an OK mid-range set of features, with a 3-megapixel camera that's capable of some good quality shots, and a decent MP3 player for tune playing.

But the InteractPad dual-screen control system is the real draw for anyone looking at pocketing the LG KF600. At the heart of the LG KF600's control system, it's a novel way to do something different with a twist on the conventional navigation D-pad.

It does offer something more graphically interesting - and certainly it's more eye-catching. Anyone thinking about this in terms of a full touchscreen, iPhone-style device, though, shouldn't - this dual-screen phone is a hybrid that is more like a standard handset in functionality than one of the new generation of large touchscreen devices like Apple's phone or LG's Viewty. Touch functionality is limited, as is the screen size for viewing content.

The InteractPad itself doesn't respond as quickly as a standard navigation pad for tapping around menus, so you may wonder what real benefits it brings - and is it a compelling reason to buy the LG KF600?

Apart from the head-turning, look-at-me gadgetry factor, the context-changing touchpad controls do make some of the functions more visually enticing, and we can see that with a bit more responsiveness the dual-screen approach could be a user-friendly option. But it's not yet a must-have technology.

With a similar sort of touchpad mobile phone device, the Samsung Soul, coming soon, the LG KF600 could be something of a trend setter. But how long-running that trend will be remains to be seen.