Under the deal, Microsoft will provide its TV Internet Protocol Television Edition software to SBC, said to be the largest DSL provider in the US, to roll out to its subscribers starting as soon as a year from now.

The deal helps SBC, an incumbent local loop carrier, break into the television market dominated by rival cable companies, while Microsoft gets a significant reference account as it plots to expand its PC dominance into new markets.

SBC said the deal of part of Project Lightspeed, a move to deploy fiber to customer households to increase capacity and enable interactive services. Lightspeed is planned to reach 18 million US households by 2007.

The company will start rolling out the new network in the first quarter. Following tests that started this June, the proposed SBC TV service will go into field trials mid-2005, the company said. Commercial availability is planned for late next year.

The major advantage of IP-based TV, from a customer perspective, is that two-way services and integration into Internet and voice over IP (VoIP) can be more easily offered. SBC is planning services such as program alerts, caller ID and instant messaging.

The service will also allow TV delivery to non-TV networked devices such as PCs and mobile computers. TV would be streamed from SBC servers nearby on demand, in contrast to normal broadcast models where everything is received at once.

The companies said Microsoft will providing the security, in the form of both digital rights management and subscriber protection, which will probably be a scary thought to many given the security troubles the firm has had in the PC arena.

Earlier this month, Microsoft secured a deployment for its TV Foundation Edition, set-top software for cable providers that consists mainly of an interactive program guide and digital recording functionality.

Comcast said it would deploy the software to one million homes in the Washington state area. The company had previously taken out a five million-seat license. Time Warner has also previously announced a trial of Foundation, but no deployment plans.