The legislation that cleared the House of Representatives in a 264 to 158 vote moves the date of the changeover to June 12 from Feb. 17. The U.S. Senate already passed the bill last month, and President Barack Obama, who supports the delay, is expected to sign it.

Updated survey information compiled and analyzed by market research firm Digital Tech Consulting (DTC) projects that 37 million converter boxes will reach consumers by summertime, now that the digital TV transition will be extended by four months.

DTC said its findings are the result of analysis of government data, interviews with converter box manufacturers and component suppliers and discussions with major retailers. DTC said last month that 33.5 million converters were shipped into the distribution system in 2008 in preparation for the mid-February transition.

DTC said it has also been monitoring rising redemption rates of the $40 discount converter box coupons issued by the U.S. Commerce Department, which now top 53 percent and have been inching upwards. To date, viewers have purchased nearly 22 million converter boxes with government coupons and DTC estimates that another four million were purchased in 2008 without the discount.

"Giving viewers more time to get their coupons, make a purchase, and connect their boxes will mean more boxes sold at retail with the $40 coupon," said Myra Moore, principal at DTC, in a statement. "The extra time and more coupon availability will likely drive converter box sales to 37 million units." Moore said.

Top sellers include converters sold under the RCA, Magnavox, Insignia, and Zenith brands, Moore said.