The arrival of Wi-Fi on smartphones has been a racing certainty for some time, but the pieces in the puzzle are coming together, with an SDIO card in development, and the future convergence of Microsoft's PDA and smartphone operating systems in prospect.

Chip design company SyChip is testing software for its SDIO (secure digital I/O) WLAN (wireless LAN) card so it can be used to add Wi-Fi capability to smartphones. With the card and the software, smartphones can use a WLAN to transmit data and double as a cordless VoIP (Voice over Internet Protocol) phone when linked to a corporate IP telephony service, said Navi Miglani, SyChip's director of marketing.

Meanwhile, Microsoft's two mobile operating systems have been recently rebranded to give an appearance of convergence: PocketPC is now known as "Windows Mobile Pocket PC 2003" and Smartphone is now called "Windows Mobile Smartphone 2003". They are still separate products, with different user interfaces determined by their heritage as data and voice products, and different capabilities (Pocket PC has Wi-Fi and Smartphone doesn't for instance). However a closer merger is on the cards, with many differences ironed out, which should bring Wi-Fi to Microsoft smartphones eventually.

Wi-Fi capability could be a welcome addition for smartphone users as it offers higher transmission speeds than current phone networks, and could be cheaper to use, for example on a corporate or home WLAN. Also, VoIP users will only need one handset that they can use as both a mobile phone while on the road and as their work phone in the office. (BT is planning to use Bluetooth to achieve this goal, in its forthcoming Bluephone plan.

SyChip's SDIO 802.11b WLAN card is currently sold as a PDA (personal digital assistant) accessory by SanDisk, ViewSonic and Socket Communications. It retails in the US for about $130. However, for smart phone use SyChip had to develop new driver software.

"Smartphones have a different user interface, with buttons instead of a touch screen. We had to develop software for that," Miglani said.

During a session at the Wi-Fi Planet conference in San Jose last week, Miglani showed a Windows Mobile-based Samsung Electronics Co. Ltd. i600 device with the SDIO card and a beta version of the driver software. A final version is due out early in 2004, along with software for Palm OS-based smart phones, he said.

SyChip is also working on software to make its SDIO cards work with smart phones based on Symbian's namesake operating system, though Miglani could not say when his company would deliver drivers for that operating system.

For now, smartphone users will have to manually install the drivers on their devices to use WLAN, a job that will most likely be done through synchronisation with a PC, Miglani said.

However, for the future, SyChip is working with Microsoft with the hope of having its drivers included in future versions of the Windows Mobile software for smart phones. Jason Gordon, product manager in Microsoft's Mobile Devices Division, could not make any promises.

"While we have nothing to announce today, one of Microsoft's top priorities is to continue to empower the Windows Mobile software and hardware developer community with both the technical tools and business support to easily develop and market solutions that allow people to connect to people and information in new ways," said Gordon in a statement.

Wi-Fi capability is valuable, but users will want to have it built into products and not in the form of an expansion card, said Michael Gartenberg, a research director at Jupiter Research.

"Many organisations will be looking for devices that have Wi-Fi functionality built in, rather than looking at the aftermarket for expansion cards. For one thing, the cards tend to protrude on some of the devices, that will certainly hamper usability. Battery life is a second issue. If I am powering an SDIO Wi-Fi card, that can severely restrict battery life," he said.

On the Samsung device, SyChip's Miglani showed the SDIO card did jut out from the side of the phone.

Phones that have Wi-Fi built in are on the horizon. In Japan, for example, NTT DoCoMo Inc. and NEC Corp. have developed a handset that supports both 3G (third-generation) cellular telephony and WLAN. The device is due out around the beginning of the new Japanese fiscal year, which starts in April.

The handset is compatible with both W-CDMA (Wideband Code Division Multiple Access) and the IEEE802.11b wireless LAN standard and is expected to be launched as a commercial product around the beginning of the new Japanese fiscal year, which starts in April, said Takuya Ori, a spokesman for NTT DoCoMo in Tokyo.

The phone will meet the dual-purpose goal, because in wireless LAN mode, the telephone supports both data transmission and, when linked to a corporate IP telephony server, voice transmission. It can double as both a regular cellular telephone and, within a company wireless network, a cordless handset and data modem.