WASHINGTON, D.C.: When President Clinton signed the massive telecommunications reform bill into law earlier this month, he put the television industry under an uncomfortable mandate: come up with a system to rate the violent content of programs, or else a government panel would impose one. Thursday, television industry leaders said they would rather rate content on their own. Emerging from a meeting at the White House, 30 industry executives announced they have agreed to create a system similar to the one used to rate movies, which describes the violent and sexual content of programs. The driving force behind a decision that the industry has staunchly resisted for years was a provision in the telecom bill calling for the v-chip, a computer chip to be installed in most television sets that would allow parents to block out programs that have been rated as high in violence or other objectionable material. The chip is useless until a ratings system is established. Now comes the difficult task of hammering out just how the ratings will be derived. Industry leaders are a long way from agreement on whether cartoons and news magazines should be rated, or how to rate soap operas. Reaching some sort of consensus should take at least six months. A final system is not expected to be in place until next January.