PDA maker Handspring introduced its next-generation Treo, the first hybrid phone and personal digital assistant to use the latest version of the Palm operating system, at the American CeBbit tradeshow yesterday.

The Treo 600 series represents a dramatic design departure from previous versions of the critically acclaimed and popular handheld. Instead of a flip-up grey clamshell, a Treo 600 has the design of a silvery candy bar. In order to accommodate the integrated Qwerty thumb keyboard, however, it is noticeably wider than most contemporary mobile phones.

Expected to ship this autumn in both CDMA and GSM/GPRS versions, the Treo 600 is based on version 5.0 of the Palm OS and uses one of the powerful ARM processors (one of Texas Instruments' Omap chips) that the operating system supports. A built-in camera can capture 640x480 resolution images.

Handspring says the Treo 600's keyboard is more ergonomic than those on earlier Treos. Users can assign keys to launch programs and specific program functions, such as opening a designated spreadsheet. Treo 600 devices will also feature a new version of the Blazer browser, which Handspring says will support more web formats.

So far, Handspring has signed a distribution deal with Orange and is discussing similar arrangements with several other operators. The outcome of these talks will determine the phone's pricing, but a Treo 600 should cost no more than the current top-of-the-line Treo 300 does today, says Brian Jaquet, a Handspring spokesperson.

That should mean the Treo 600 eventually retails for around £300, making it a strong competitor to Samsung's soon-to-be-released I600 PDA ? and in more ways than one.

While the I600's clamshell design makes it much narrower than the Treo, Samsung's smartphone has no keyboard. When flipped shut, the I600 is significantly shorter and just a little thicker than Handspring's device, however it is based on Palm OS 4.0, uses a much less powerful processor than the Treo 600, and lacks the SD expansion slot present on most newer Palms. So far, Samsung has not announced plans for a GSM/GPRS version of the I600.