WASHINGTON — After weeks of debate, Congress is giving consumers four more months to prepare for the upcoming transition from analog to digital television broadcasting.

The House voted 264-158 on Wednesday to postpone the shutdown of analog TV signals to June 12, to address growing concerns that too many Americans won’t be ready by the Feb. 17 deadline that Congress set three years ago. The Senate passed the measure unanimously last week and the bill now heads to President Barack Obama for his signature.

The change is being mandated because digital signals are more efficient than analog ones. Ending analog broadcasts will free up valuable space in the nation’s airwaves for commercial wireless services and emergency-response networks.

The delay is a victory for the Obama administration and Democrats in Congress, who maintain that the previous administration mismanaged efforts to ensure that all consumers — particularly poor, rural and minority Americans — will be prepared for the switchover.

The Nielsen Co. estimates that more than 6.5 million U.S. households that rely on analog TV sets to pick up over-the-air broadcast signals still are not ready. People who subscribe to cable or satellite TV or have a newer TV with a digital tuner will not be affected.

“The passage of this bipartisan legislation means that millions of Americans will have the time they need to prepare for the conversion,” White House spokeswoman Amy Brundage said in a statement.

Wednesday’s vote came one week after House Republicans blocked the bill under a special fast-track procedure that required two-thirds support to pass. This time, the bill passed the House under a regular floor vote, which requires a simple majority.

Among Democrats, 241 voted for the bill, while 10 voted against it. Among Republicans, 23 voted for the bill, while 148 voted against it.

Speaking on the House floor Wednesday, Rick Boucher, D-Va., chairman of the House Commerce Committee’s Subcommittee on Communications, Technology and the Internet, said a delay was needed to prevent the digital transition from becoming a failure.

“It is unfortunate that Congress had to take additional action on this issue, but the prospect of leaving millions of consumers in the dark was simply unacceptable,” subcommittee member Edward Markey, D-Mass., added.

Opponents of a delay warned, however, that the move will confuse consumers, create added costs for TV stations that will continue broadcasting both analog and digital signals for four more months and burden wireless companies and public safety agencies waiting for the airwaves that will be vacated by the switchover.

“It’s time for us to move forward on this and keep our word to the American people,” said Rep. Marsha Blackburn, R-Tenn., calling for the transition to proceed on Feb. 17.

Democrats have tried to address these concerns by allowing broadcast stations to switch to digital signals sooner than June if they choose, potentially freeing up spectrum for public safety early. But it is unclear how many TV stations plan to take advantage of this option.

The Consumer Electronics Association, meanwhile, is warning that a delay could result in a shortage of converter boxes that translate digital signals back into analog ones for older TVs. Manufacturers and retailers have planned inventory based on a Feb. 17 transition date.

The new administration called for the digital transition to be postponed after the Commerce Department last month hit a $1.34 billion funding limit for coupons that subsidize converter boxes for consumers. The coupon program allows consumers to request up to two $40 vouchers per household to help pay for the boxes, which generally cost between $40 and $80 each and can be purchased without a coupon.

The National Telecommunications and Information Administration, the arm of the Commerce Department administering the program, is sending out new coupons only as older, unredeemed ones reach a 90-day expiration date and free up more money. The NTIA has more than 3.7 million coupon requests on a waiting list — and those people would not receive their coupons before Feb. 17.

A separate measure, part of the economic stimulus proposal working its way through Congress, would add $650 million in funding for the coupon program.

Democrats on Capitol Hill and at the FCC have also questioned whether the government has provided enough on-the-ground support to help consumers hook up converter boxes — or whether enough call center resources have been arranged to handle what could be an avalanche of requests for help.

“The country is not prepared to undertake a nationwide transition in 12 days without unacceptably high consumer dislocation,” acting FCC chairman Michael Copps said in a statement. “We’ve got a lot of work to do, but we now have an opportunity to do it better.”

The National Association of Broadcasters also welcomed the delay. The group said it will provide new television spots to promote the June 12 deadline, and work with stations to coordinate additional analog shut-off tests to raise awareness and help consumers prepare.