PORTLAND – Maine PBS has completed a federally mandated $20 million conversion to digital broadcasting, providing television viewers across the state with access to four digital channels of PBS programming.

In addition to the standard Maine PBS network lineup, the digital channels include: Maine PBS Kids, a selection of children’s shows; Maine PBS You, an educational channel; and Maine PBS Plus, which includes national PBS programs.

An estimated 40,000 Maine households now receive the new digital channels, either through digital cable service or set-top converter boxes that cost around $300 each.

Maine PBS is able to broadcast four channels of programming because digital broadcasting takes up less space on the airwaves than analog broadcasting. The federal government has mandated digital conversion for all TV stations to clear air-wave space for other technologies, including cell phones.

In the future, Maine PBS officials hope to use the digital channels to bring viewers more choices of programming, both national and local.

“Right now we have these four digital channels, but the way the technology is going, we might have eight tomorrow,” said Gil Maxwell, senior vice president and chief operations officer for Maine Public Broadcasting, which includes the five TV stations of Maine PBS. “Before digital, we were limited in the choices we could present to viewers. This really expands what we could do.”

In 1999, Maine voters approved a $9.4 million bond issue to help Maine PBS’ conversion to digital broadcasting. But since then, Maine PBS was able to save the state $1.6 million by landing a grant in that amount from the National Telecommunications and Information Administration. The agency’s grants were given to a select number of public broadcasters nationwide.