In a petition to FCC filed Thursday, the Community Broadcasters Association says that converter boxes that block analog signals are illegal under the All-Channel Receiver Act, which requires TV receivers to enable display of all available TV signals. The CBA says that boxes planned for sale by Samsung and EchoStar in conjunction with the government's program of $40 coupons <http://www.ntia.doc.gov/dtvcoupon/index.html> will behave like VCRs and thus comply with the law-that is, they'll pass through whatever signal comes through the antenna when the box is off on in a "TV" mode. But the other boxes, CBA says, will not. CBA had told the National Telecommunications and Information Administration, the office charged with overseeing the coupon program, that it should require the eligible boxes to receive regular analog signals with a pass-through mechanism such as a toggle switch, said Peter Tannenwald, attorney for CBA. But NTIA's rules made that feature permissible, but not mandatory. "I don't think it occurred to us in the beginning that manufacturers would make their products that way," Tannenwald said. He said the Samsung and EchoStar boxes would still be eligible for the coupon program if the FCC acted on the complaint, and other box makers have plenty of ways to come into compliance. www.tvtechnology.com/pages/s.0157/t.10131.html