The second model in the Xda II range, the O2 Xda IIs offers users an extensive array of features, delivering both a fully featured mobile phone and PDA.

Weighing 210g with a lithium polymer battery, the IIs is large compared to other smartphones (such as the Palm Treo 650), which makes the included case with belt clip almost essential. It scores points in the looks department, with a sleek black matte finish, and is dominated by the large 3.5" TFT LCD colour screen.

With a 240 x 320 resolution, the screen is bright enough to be used outdoors and provides plenty of room for working on calendar, tasks and Office applications. One useful feature is the ability to choose between portrait and landscape views, allowing full use of the screen width and height.

The IIs ships with Microsoft Windows Mobile 2003 Second Edition, and is powered by an Intel PXA263 400MHz processor, meaning that multiple applications can be run concurrently. The standard Office applications come pre-installed as well as some basic games and a PowerPoint/PDF viewer. Email users will be happy with the Pocket Outlook interface and Calendar, while data services such as SMS, MMS and even instant messaging (through MSN) are all supported.

The IIs has 128MB of RAM and 96MB flash ROM integrated, and has an expansion slot for MMC/SDIO, allowing up to 2GB of extra storage.

The controls and buttons on the unit are well laid out, with the stylus hidden in the back and a five-way navigation button at the bottom. Buttons are provided for easy access to frequently used applications like the Calendar, Contacts, Camera, Email and Inbox. Dedicated Call Start and End buttons are located at the bottom of the unit.

The IIs provides a variety of data entry options, such as an onscreen keyboard, character recognition software and a small slide-out keyboard. While having a keyboard is useful, we found the keys small and not well spaced, taking some time to get accustomed to. A 2.5mm Pocket PC phone jack for headphones is also provided, but standard headphones can't be used with the IIs without an adapter. The sound quality was quite good when making calls.

The IIs really wins in the connectivity stakes, supporting GPRS, Bluetooth, infrared and Wi-Fi. It makes synchronising email or browsing the Net extremely simple. In terms of security, the IIs supports both WEP and WPA.

Although O2 claims the lithium polymer battery supplies four hours of continuous talk time and can last for 168 hours on standby, mobile users will need to recharge every 24 hours and a spare battery is essential for heavy users. The extra battery costs $90 and the unit takes three hours to recharge.

Retailing at $1,599, the IIs is pricey, but has a range of organiser functions and wireless connectivity options to please even the most demanding of users.