Wireless developer Commtag has announced it is working with leading Bluetooth chipmaker Cambridge Silicon Radio (CSR) to promote Bluetooth applications, beginning with Commtag's always-on email software.

Commtag will this month ship Duality, an application that pushes email messages to mobile staff with handheld PDAs. The firm sees Bluetooth as a key technology to make Duality work, and said that its partnership with CSR is important for that reason. Over half of all Bluetooth devices are based on CSR's chips, according to the firm.

"We have a mutual interest in pushing Bluetooth forward," said Commtag chief executive Geoff Baird. "CSR wants to see applications that are useful, and we get access to its Bluetooth drivers."

Baird said the partnership with CSR did not mean that Duality would only work with CSR chips. "We need to work with all Bluetooth devices," he said, adding, "but [Duality] must work in a reliable and consistent way, and CSR can help with that."

The Duality application forwards messages from a corporate mail server to a handheld via an Internet connection to Commtag's relay server. The relay server stores messages if the handheld is turned off, or if the wireless connection is dropped. "We basically use a Bluetooth-enabled GPRS phone as a router to get data to the PDA," said Baird.

Bluetooth was the best solution for this final link, according to Baird, because it was more convenient and reliable than cables or infrared. So long as a user's phone is within a few metres of their PDA "you get email updates all day", Baird said. The client software is currently available only for handhelds running Pocket PC 2002, but Symbian and Palm OS versions are being developed.

In future, Commtag hopes to add roaming capability to Duality. This would allow employees to route email directly to their PDAs via Bluetooth access points while on-site, seamlessly switching to the GPRS connection outside the premises.

Duality runs on Windows 2000 servers and links to Microsoft Exchange Server 5.5 and 2000. It will cost £3,000 for 20 users, plus charges of £10 per user per month.

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