Schwartzman questioned the public-service campaigns being planned to tell consumers that older TV sets won't work without converter boxes after the digital transition. He said they won't reach those who need assistance the most, including non-English speakers, seniors and the poor. "I really fear for it," he said. "The people who are going to be hurt are the people at the bottom."

Another concern is that a National Telecommunications and Information Administration coupon program to subsidize the boxes will fall short. The vouchers are designed to help analog-dependent TV viewers purchase devices that will keep their sets functioning after the Feb. 17, 2009, switchover. Millions of coupons need to be at bodegas, laundromats and other neighborhood venues, not just electronics stores, Schwartzman said.

He also warned that the transition would be undermined without mandatory cable carriage of ancillary digital signals and by broadcaster opposition to freeing unused TV spectrum for unlicensed devices. The cable industry says the government should not dictate the stations it carries, and broadcasters warn that use of dormant "white space" spectrum might interfere with DTV reception.

Echoing his views was Gloria Tristani, a former FCC member and now a communications attorney. She is fluent in Spanish and complained of inconsistent terminology for Spanish speakers on industry and government Web sites promoting the transition.

NTIA chief John Kneuer sharply disagreed with the gloomy predictions, which he described as "apocalyptic." He said many positives would result from the changeover, including more revenue for the treasury, due to the upcoming auction of analog airwaves, and more frequencies for public-safety officials.

During his speech, Kneuer outlined ambitious plans to reach ethnic populations by distributing material about the transition in Chinese, Japanese and other languages, and by working with seniors groups. "Clearly we recognize that this has got to be a broad partnership. I'm confident that we're going to get this message out," he said.

Congress has provided NTIA with $5 million to inform the public about the vouchers, to be buttressed by millions more through industry-donated advertising.

"I get a little frustrated sometimes when people stand up and tell us all the things we should be doing," said David Rehr, president of the National Association of Broadcasters. The industry needs "everyone's help" to assist with this "Herculean effort," he added.