Microsoft's internet television software received a big endorsement on Tuesday when BT Group, a UK telecommunications operator, said it would use the technology to deliver videos over broadband lines in the UK.
BT's decision is a key win for Microsoft, which has been battling for years to win customers for its internet protocol TV (IPTV) software that enables telecoms carriers to offer a wide range of advanced broadband video and other services in direct competition with cable TV groups.
The BT deal may help quell some of the doubts raised about the software last month, when Swisscom, which is also trying the Microsoft platform, announced it would have to delay the launch of its video service until 2006 because of technical problems.
Microsoft has acknowledged that its partners have encountered problems, but said its software was not responsible.
In addition to BT and Swisscom, Microsoft has deals in Europe with Telecom Italia and Deutsche Telekom's T-Online France unit. However, Swisscom and BT are the only European customers so far to have confirmed they are planning to use the technology for a commercial launch.
In the US, Verizon Communications, SBC Communications and BellSouth, the three biggest US telecoms groups, have also announced plans to use the Microsoft software to deliver digital TV over the new fibre optic-based broadband networks they are building.
Telecoms groups are looking to launch ?triple-play? services, offering bundles of pay-TV, high-speed internet access and voice calls to customers, to offset falling prices of voice-only business. BT plans to start trials of video-over-broadband services early next year, with commercial launch in the summer.