Samsung has produced a breathtaking spread of phones over the last couple of years. But out of all the various designs that the Korean giant has unleashed, two have been particularly memorable.

The D500 and its successor, the D600, were - in fact, still are - highly-desirable mid-market handsets. Produced in an all-black casing, and given that frisson of cool through the use of a semi-automatic slide-open mechanism.

The pair do enough to attract the executive user as well as the gadget freak. The new Z400, though, offers something neither of these models has - 3G.

Sure, like the D600, it offers a 2-megapixel camera and an MP3 player with an expandable memory, and it also does the business with document readers that can read all sorts of files that come attached to emails.

Performance boost

Now, though, with the Z400 Samsung has supercharged the slider concept by adding the highspeed multimedia capabilities that third generation devices are capable of - including video calling, high speed video and audio downloads and streaming.

Samsung, so far, has concentrated mainly on producing clamshell handsets for the burgeoning 3G market. The Z400 is not quite the first Samsung with a slip-open casing: the Z320i sold exclusively in this country by O2 offers a unique combination of 3G and i-mode operability. But this is a handset that everyone should sit up and take notice of...

Samsung has decided (initially at least) to deliver the Z400 in chrome rather than black, to differentiate it from the D600. Remarkably, the Z600 is actually slightly lighter and slimmer than its GSM predecessor.

The large 320x240-pixel display gets put to full use in the slider design, being permanently on view, and can be used to provide access to every piece of information, download and file that the phone presents you.

When it comes to viewing streamed videos and so on, the size and quality of the screen is essential to the viewing experience. Software makes good use of the available space on occasion; when you use the video conferencing facility, you get a good sized preview of yourself as you dial.

This shrinks vision-mixer-style to a corner when your call is actually answered, so you can see the incoming picture clearly. The space is not used so well when watching videos or Mobile TV - there is no way to blow up the picture so that it fills the full LCD area; instead you get an image that occupies only the central 65 per cent of the display.

Furthermore, there is no one-touch button for placing a video call - so you are required to delve into the menu options to use this.

Quick access

You do get a button on the side of the phone that offers quick access to a number of onboard application - and this proves particularly useful when using the phone without going to the trouble of revealing the full numberpad.

There is also a fastkey for the camera, although with this the slider is best opened, otherwise you can only use the VGA resolution secondary camera, which is primarily designed for videoconferencing.

Samsung has developed a great reputation for its onboard digital cameras. And with a maximum resolution of 2 megapixels from the main lens, the Z400 carries on with the tradition. To be fair to other manufacturers, the camera is no longer state-of-the-art in terms of resolution or facilities; there is no flash, let alone autofocus mechanism or macro mode.