WASHINGTON — Broadcasters are prepared to cave in over content-based TV ratings. Under a new plan backed by the National Assn. of Broadcasters, the current age-based ratings system would add symbols giving viewers specific information about a show’s violence, sexual innuendo and adult language.Industry reps and key members of Congress are working on a deal that would give Congress the beefed-up TV rating system it has been clamoring for — and the industry had fiercely resisted — in return for a moratorium on content-related legislation. After meeting with network lobbyists Wednesday evening, Senate Commerce Committee chairman John McCain (R-Ariz.) gave broadcasters 10 days to finalize the details of the proposed agreement. If they fail to come up with an acceptable answer to critics of the current TV code, he promised to move forward on June 18 with a bill that makes the transition to digital TV contingent on the adoption of a content-based rating system. The legislation is sponsored by Sen. Dan Coats (R-Ind.). The Coats bill will become irrelevant if broadcasters can get public-interest groups such as the American Medical Assn. and the National PTA to sign off on a proposal backed by the National Assn. of Broadcasters. Under the NAB plan, broadcasters would add V, S and L icons to their current age-based rating system. V would indicate a show has violent content; an S would indicate sexual content and an L would tell parents that the show contained adult language. McCain and other members of Congress who participated in Wednesday’s meeting said any agreement must also be blessed by the key public interest advocates. But if broadcasters can line up support for a modified rating system, McCain and other congressional leaders promised to block any content-related legislation on Capitol Hill for several years. After the meeting, McCain also seemed optimistic that such a deal could be worked out. “If there is agreement, we must hold up our end of the bargain,” said McCain, who added that congressional leaders were willing to make such a commitment. House Telecommunications Subcommittee chairman Billy Tauzin (R-La.) also said Wednesday that such a deal could be palatable on Capitol Hill. “There should be a long period of time where they don’t have to be worried about being beaten up,” said Tauzin. The Telecommunications Act of 1996 mandates that TV set manufacturers install an electronic blocking device, known as a V-chip, in TV sets sold in the U.S. With the V-chip, parents will be able to block shows based on their particular rating. Although it was never specifically addressed during the meeting with industry lobbyists, Rep. Ed Markey (D-Mass.) said he expects the industry to agree within two weeks to add the V, S and L labels to their current age-based code. Network sources and others involved in the development of the current ratings code also said they would gladly agree to V, S and L, if they could be assured Congress would stop attempting to influence TV programming through legislation. The lone holdout is NBC, but other lobbyists insist that the Peacock web would relent once the deal was sealed. But some network sources say there is no guarantee that congressional leaders can keep up their side of the deal. They were particularly worried because Sen. Ernest Hollings (D-S.C.) did not participate in Wednesday’s tete a tete. Hollings has a bill of his own, which would ban all violent programming on television during times when children are most likely in the audience. The bill does provide an exception for violent shows that are labeled with a content-based label.