The Celio RedFly is a device that connects to Windows Mobile smartphones to give them a readable 800x480-pixel screen and a cramped but usable qwerty keyboard.

The drawbacks

In our tests, the Celio RedFly mostly succeeded in moving the experience of using a smartphone toward that of working on a laptop.

However, there are some drawbacks, most of which result from the fact that, no matter how much the Celio RedFly makes a smartphone work like a laptop, you're still depending on a phone and its limited processor, operating system, applications and storage.

Web surfing is one example. The good news is the Celio RedFly provides a 800x480-pixel screen and keyboard, all significant advantages over a standard smartphone. The bad news is that you're still running Windows Mobile. That platform's Internet Explorer Mobile browser is, arguably, a highly constrained way to browse the web.

Add to that the limited processing power of a smartphone and network access that's likely to be slower than your home broadband connection. The bottom line is a browsing experience that will be much slower than you are accustomed to.

Moreover, while the Celio RedFly does some screen reformatting, many sophisticated websites automatically detect device and browser settings and switch into a "mobile" display mode that presumes a 320x240 display. The resulting paradox is that, the more sophisticated the website, the worse the result on the Celio Redfly.

For instance, in Google's Gmail, the text box for writing an email message stays the same width on the Celio RedFly's screen as it is on a smartphone display. In other words, the text box is less than 300 pixels wide and hugs the left edge of the Celio RedFly's screen.

This problem also afflicts some applications installed in the phone; the more graphics-intensive the app, the less Celio's RedFly can do to remap it to the larger screen. With the Solitaire game on the HTC Tilt used for these tests, the width stayed the same size on both the smartphone and RedFly screens, which made the individual cards smaller than Windows Mobile's icons on the Celio RedFly's screen.

Fortunately, the Office Mobile applications work quite well on the Celio RedFly, using the entire screen. Of course, these are scaled-down versions of Office applications, so they don't include the whole range of formatting options, but the basics are there. Once you've adjusted your typing to the delicate touch required by the smaller Celio RedFly keyboard, you can touch-type in Word at a speed that outruns the display.

Wide appeal

The Celio RedFly's ability to combine wireless connectivity with just enough hardware to do real work should make it a hit not just with road warriors but also with IT departments.

Users will love the Celio RedFly because it can increase productivity. One reason IT departments will love it is that there's nothing to install or maintain on device, and very little training and support is required. As a dumb terminal, there are no security risks if it gets left in a cab. And there's no upgrading required if the user gets a new phone.

While Celio has no immediate plans to provide drivers for other smartphone operating systems, the company says there are no technical barriers to someday expanding beyond Windows Mobile. And some Palm Treo and BlackBerry users will surely clamour for the RedFly, if it becomes available for them.

OUR VERDICT

Celio's RedFly is yet to be introduced in the US, and we European users may have a long wait – and that's if it even takes off and crosses the pond. We can't help being reminded of Palm's ill-fated Foleo - and at $499 (£250), it is a little pricey. However, the RedFly does a good job of turning your smartphone into a proper laptop to aid productivity, and that's just one of its benefits.