Broadcasters are urging the Federal Communications Commission to allow them full entry into new technologies such as high-speed data transmission to help pay for the conversion to high definition TV.In a petition filed at the FCC, the National Assn. of Broadcasters said new services such as high-speed data broadcasting could provide an estimated $ 400 million in revenues to help offset the high cost of HDTV conversion. Allowing broadcasters to deliver data to subscribers of computer information services such as Prodigy would be a boon for consumers and businesses, the NAB claims. The broadcast industry has been grumbling over FCC plans to force TV stations to convert to HDTV within 15 years. Some station owners have expressed fear that the high cost of conversion could drive many broadcasters into bankruptcy. In its comments to the FCC, the NAB said a government-set timetable for converting to HDTV is inappropriate.