Public TV stations and cable multiple system owners reaching more than 80 percent of cable homes have ratified a deal that will ensure carriage of public broadcasting’s digital TV signals on systems serving “the vast majority of the nation’s cable subscribers,” according to a joint release Thursday by the National Cable & Telecommunications Association and public broadcast groups.

Under the deal, which was originally announced in January, cable systems will begin adding the digital signals of public TV stations to their lineups this year.