The XDA Mini S from O2 is a compact PDA/phone handset that offers quad-band GSM capability plus Wi-Fi and Bluetooth wireless functions. It also has a hideaway qwerty keyboard that makes it easier to write emails and edit documents.

Shipping since November, the new XDA model is similar in size and shape to a bar of soap and weighs about 160g. This puts it about halfway between other Pocket PC phones and standard handsets.

We found this format to be a good compromise between size and functionality, especially for staff who need to keep in touch by email while on the move, but do not want to be lumbered with an oversized brick for voice calls.

The XDA Mini S is small enough to be held to your ear like a standard phone when making calls. However, O2 also ships it with a wired stereo headset that features a talk button and volume control. The device has 64MB memory and has a Mini SD slot for Flash storage cards.

Like many Windows Mobile devices, the new XDA is made by HTC and very similar models are available from other carriers.

Because of its small size, the XDA Mini S has only a 2.8in colour screen. However, this is a relatively high-resolution type at 240x320 pixels, and we found it bright and clear. In phone mode, the on-screen number keys are a little small but we were able to dial using a finger or thumb instead of the stylus. The screen and entire front panel of the device slide to the right to reveal a keyboard. At the same time, the screen automatically changes to landscape mode to match the keyboard orientation.

In this configuration, we found it easy to cradle the device in both hands for thumb typing. Although users should not expect to get up to any great speed, it does make text entry easier. Users can alternatively use an on-screen keyboard or write on the display.

The XDA Mini S runs Windows Mobile 5.0, so its built-in Word, Excel and Pow erPoint applications are file compatible with their desktop equivalents. Other applications include a Zip compression tool, Voice Speed Dial, and a Hotspot Directory of Wi-Fi access points in the UK. Pocket MSN is also included, which has MSN Messenger for instant messaging.

The 802.11b Wi-Fi capability allows faster access to web content and email. However, we found that the XDA Mini S would often drop its Wi-Fi connection during a session. Our review model was also not configured for internet access via GPRS, but we easily found the correct Access Point Name (APN) and server settings listed by searching O2's web site.

The XDA Mini S has a removable battery that should last for up to five hours of talk time or 200 hours on standby. It can be charged via a mains adapter or via a USB connection to a PC. Next to the battery compartment is an integral 1.3 megapixel camera with flash.