At noon sharp Thursday in Hawaii, a message appeared on analog TV sets across the islands: "All full power Hawaii TV stations are now digital."
The state shut down old-fashioned broadcast signals, more than a month before the rest of the country is set to make the now-contentious switch.
Residents lit up special TV help center phone lines set up by the Federal Communication Commission and broadcasters. By evening, calls were coming in at nearly 100 an hour.
On home screens, the shutdown message flashed for about a minute in white text on a blue background. Then, a seven-minute announcement video began a broadcast loop that will continue for several weeks on major island stations.
Technicians are calling it the "analog night light."
Officials at the call center made last-minute checks with some 20 TV stations around the islands, with all reporting they were ready.
"The smart people have already converted," said John Peters, president of the Honolulu Amateur Radio club and a volunteer at the help center. "The people calling in today are the ones who didn't prepare in advance."
Experts taking the calls quickly screened out anyone with cable or satellite service, because they are unaffected by the switch. But some confusion had been expected.
"No matter how many commercials we run, there will always be a certain part of the population that doesn't get the message," said Chris Leonard, president of the Hawaii Association of Broadcasters, who was helping out at the call center.
One glitch cropped up even before the switch, with the PBS station on the Big Island reporting it hadn't yet received equipment to send its digital signal to an area of the island that is the southernmost point in the nation, South Point.
PBS has been the only station serving the rural area. The problem was expected to last for several days.
Another station on the Big Island, ABC affiliate KITV, reported a mechanical problem in its digital transmitter that delayed the transition, but the problem was solved after about three hours.
With analog TV signals turned off, residents with older TVs were finding out whether they will be missing any channels or whether they still have any service at all.
Government officials and broadcasters estimate about 20,000 households in Hawaii still get their TV signals over the air, meaning they'd have to buy new TVs with digital tuners or digital converter boxes for their old TVs.
"It's really amazing how many people wait until the last minute," said June Gonzales, a member of the FCC team.
Households that need but failed to buy digital converter boxes would miss Thursday night shows like "CSI" or "Grey's Anatomy."
Others who bought the $50 to $70 converter boxes might still find they lost channels because digital signals won't necessarily reach all the places hit by analog broadcasts.
Hawaii was moving to all-digital TV before the Feb. 17 date set for the rest of the nation because of an endangered bird, the Hawaiian dark-rumped petrel.
Broadcasters and park rangers want to take down analog transmission towers on the slopes of Maui's Haleakala volcano before the bird's nesting season.
The analog shutdown in the rest of the country -- which Congress mandated to free up space in the airwaves for other wireless services -- has been put in doubt because the government has run out of money for $40 coupons to subsidize converter boxes.
President-elect Barack Obama's transition team has asked Congress for a delay.
One key Democrat, Senate Commerce Committee Chairman John D. Rockefeller of West Virginia, introduced a bill Thursday that would postpone the transition to June 12.
Democrats on the House Appropriations Committee are also including $650 million in funding for the coupon program in their economic stimulus proposal.
Despite extensive preparations and a broad public educational effort, the government and broadcasters are prepared for a torrent of complaints when analog TV dies.
In Hawaii, hundreds of calls for help already have been pouring in daily to the statewide customer support center.
Some TV stations have put messages on their phone answering systems referring callers first to the support center.
Teams of volunteers and contractors have been making house calls to residents who were having difficulties with the converter boxes, but they may not be able to reach everyone throughout the islands Thursday if there are widespread problems, especially in rural areas.