Sales of Wi-Fi phones increased by more than 60 percent last year, according to Infonetics Research, as vendors have done more to support wireless IP (Internet Protocol) telephony.

Last year vendors sold 682,000 Wi-Fi phones worldwide, compared to 358,000 in 2006. There are several explanations for the increase.

"IP telephony has matured, and wireless LANs have also matured. Companies started to build wireless LANs to put data on them, but now they are looking for other applications," said Richard Webb, directing analyst, WiMax, Wi-Fi, and Mobile Devices, at Infonetics Research.

Vendors such as Cisco Systems and Aruba Wireless Networks have also added features to network hardware to make wireless IP telephony a much easier proposition compared to a couple of years ago. Interoperability tests have also helped, according to Webb.

The sales increase is impressive, according to Webb. But the Wi-Fi phone market is only a couple of years old and even if the market shows high growth rate it is compared to low volumes.

The Wi-Fi phone market is dominated by Cisco and Polycom, which both had 33 percent of the market during the fourth quarter of last year. Cisco especially has seen a high growth.

"In the beginning of the year Cisco was behind Polycom, but over time it caught up, thanks to its enterprise sales muscle," said Webb.

Over time mobile phones with support for Wi-Fi will take over, but there will still be a market for Wi-Fi phones, according to Webb.

"Not all companies want to give employees a mobile phone," said Webb.