Casio Cassiopeia A-20

Last year saw some changes in the PDA market. First, US Robotics stomped in with the Pilot, which turned the PDA paradigm on its head; Psion then fought back with the Series 5, and Microsoft pushed into the brawl with Windows CE.

Now the smoke has finally cleared, it's surprising to see that some fighters are still standing. The Pilot is now under 3Com's control, the Series 5 has spawned a clone in the shape of the Geofox, and Microsoft - surprise, surprise - is attempting to control everything via an OS. Hardware vendors such as Philips, Hewlett-Packard, NEC, Compaq and others have all launched WinCE-powered HPCs, proving that Windows CE can't be written off. In fact, it's actually improved.

After the impressive debut last month of HP's 620LX (reviewed issue 41,p180), followed by Sharp's innovative HC-4500 (reviewed p167), this month it's the turn of Casio's Cassiopeia A-20. Although it certainly won't turn as many heads as either HP's or Sharp's models, it's more than £200 cheaper, is smaller and is a lot more likely to fit in the average pocket.

Opening up the Cassiopeia's stylish gunmetal grey case, you might think there's been a mistake when you switch on the power. But Casio has made a deliberate choice to go with a four-greyscale 640 x 240 screen, instead of the eye-opening 256 colours supported by the 620LX. It's a surprising choice, as WinCE 2 supports up to 16 shades of grey. Nonetheless, the Casio's display remains clear and usable, if a little too dim for anything below normal lighting conditions. To compensate, there's a backlight included which can be set to switch off after a user-definable idle period.

Casio claims the Cassiopeia will run for 25 hours on two AA batteries. Of course, heavy use of the backlight, the Type II PC Card slot and the PC connector cable will diminish this. Curiously, as the batteries ran low on our test model, the backlight developed an attitude, switching off after only a few seconds of use and refusing to come back into operation.

The Cassiopeia's keyboard won't win many fans. The keys are reminiscent of a scientific calculator keyboard. It's not that the action is bad, more that the keys are so small and fiddly that typing at any sort of speed is a feat of digital dexterity. I'd also challenge anyone to hit the or keys without pressing the key at the same time, without looking at the keyboard. I did get used to it after a while, but the keyboard on the Psion Series 5, or even the Series 3, is still better.