SBC Communications, the second-largest phone company in the United States, on Thursday unveiled details of a $4 billion fiber-technology initiative that would enable the company to offer video, voice and data services starting in late 2005.

By deploying fiber technology directly to homes in new housing developments and to neighborhoods in more established communities, SBC said it will begin constructing its new network next year, with plans to introduce video services by the end of the year. By 2007, SBC expects to have its fiber technology available to about 18 million households, or half its footprint.

Offering some form of discounting for customers who take SBC’s bundled package of TV, phone and high-speed data, SBC officials hope in five years to reach a 20 percent market penetration, making it the second-largest provider of pay-TV services in the areas where fiber technology is available. If it achieves that goal, SBC said it would surpass the penetration rate of satellite companies EchoStar Communications and DirecTV Group, and be second only to the cable companies operating in those communities.

What the fiber launch could mean for EchoStar, which has an alliance with SBC to bundle their services, remains unclear. While EchoStar has warned that growth derived from the SBC-EchoStar alliance could slow as the fiber service is rolled out, an SBC official maintained that its partnership with EchoStar will remain intact even with the introduction of the fiber service.