Global sales of personal digital assistants (PDAs) have rebounded to record levels in the first quarter of this year, Gartner has reported.

The figures, which revealed a year-on-year increase of 25 percent to 3.4 million units, will confound widespread predictions that the handheld computer sector is set for a slow and loss-making death.

The stats show that the unexpected sales rise has its winners and losers. Research in Motion’s Blackberry is now the world’s top-selling handheld computer, taking the company’s market share to 20.8 percent. In contrast, PalmOne’s share has dropped to 18 percent from the 30.5 percent it enjoyed a year previously.

In terms of software, during the same period Microsoft’s Windows CE platform accelerated its previously slow ascent, rising from 42.2 to 46 percent market share, while Palm OS dropped precipitously from 40.9 percent to 20 percent.

Gartner’s explanation is that growth in PDAs is now being driven by interest in wireless connectivity, which matured noticeably during 2004. As these models tend to be expensive, it also helped boost the average selling price by 15 percent to a record $406 per PDA.

"PDAs with integrated wireless local area network (LAN) or cellular capabilities accounted for approximately 55 percent of all PDAs shipped in the first quarter of 2005," said Gartner’s Todd Kort.

There was also evidence that customers had warmed to models that featured larger displays and basic QWERTY keyboards that allowed two-fingered text entry, he said.

Oddly, one of the shining examples of this type of PDA is Palm’s Treo series, which Gartner’s figures show as the OS platform now sinking fast in sales terms. This suggests that offering customers the wrong sort of product might only be part of the problem, and that the real innovation in a maturing market is now in the selling chain.

Our recent review of the latest Palm Treo 650 praised its design on many points, but criticised it for being under-specified in terms of built-in memory. In a separate review of the Treo 650’s SD-based WiFi upgrade card, we noted that the same wireless connectivity was integrated into rival Windows CE and Symbian devices for no extra cost.

Either way, the figures will come as a blow to Palm, which a decade ago was able to successfully reinvent the idea of handheld computers from the wreckage of Go Computer and Apple’s failed attempts to popularise pen computing in the early 1990s.