Denmark joins a growing number of countries where households and small businesses can buy converged Wi-Fi-cellular services.Starting\u00a0Friday, the Danish subsidiary of Sweden\u2019s TeliaSonera will offer a service that allows users to make Wi-Fi calls at home and cell calls on the move, said TeliaSonera Denmark spokesman Rune Fick Hansen. For 189 Danish kroner (US$32) per month, a household of up to five people can make unlimited calls to family members and all fixed networks in the country. Samsung Electronics\u2019 SCH-P200 will be the only dual-phone available at launch, but Telia Denmark is in talks with Motorola and Nokia to add more handsets, according to Hansen.The Danish service, Home Free, is similar to the T-One service launched earlier this month by Germany\u2019s Deutsche Telekom and the Fusion service rolled out last year by Britain\u2019s BT Group.Though usage is similar among all three services\u2014customers use one phone that operates on two different networks\u2014each offering has some technical differences, for good or bad.Unlike T-One, which requires users to subscribe to Deutsche Telekom\u2019s DSL service, Home Free allows customers to freely select their broadband service provider, whether cable, fixed line or wireless LAN."Cable is really big in Denmark, and we have many new companies providing Wi-Fi services in apartment buildings and other public areas," said Hansen. "No one is forced to purchase a broadband connection from a sole provider." Like T-One, which requires customers to buy their cell phone service from Deutsche Telekom\u2019s mobile subsidiary, Home Free gives users only one cell phone option: TeliaSonera.Another distinction: T-One and Home Free use different technologies to move calls between Wi-Fi and cellular networks. The German offering is based on Session Initiation Protocol, while the Danish service uses unlicensed mobile access (UMA) technology. UMA enables a "seamless" hand-over of voice and data connections between global system for mobile communications and Wi-Fi or other local wireless networks. Additional information about UMA is available here.BT\u2019s Fusion service, which initially launched using Bluetooth but has since added Wi-Fi to extend its range, also uses UMA to hand over calls between cellular and local wireless networks. TeliaSonera Denmark and BT aren\u2019t alone in their use of UMA. The U.S. mobile arm of Deutsche Telekom, T-Mobile USA, is conducting a UMA-based pilot in Seattle, Wash. Telecom Italia and Orange also have UMA plans of their own.Numerous manufacturers are eager to break into the nascent market for converged Wi-Fi-cellular phones. Earlier this year, Nokia announced its first UMA-based phone, the 6136. The world\u2019s largest mobile phone maker is conducting an UMA pilot with local infrastructure providers in Finland. Koninklijke Philips Electronics now offers a complete UMA semiconductor reference design that handset manufacturers can license to build their own converged phones.-John Blau, IDG News Service (Dusseldorf Bureau)Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.