The cell phone industry is adopting a rating system for its multimedia services to designate which music, video and gaming products are intended for adults and provide tools for parents to block access to that content.

The ratings and parental tools would not, however, stop youths from using the wireless Internet connections on their mobile phones from accessing public Web sites that feature content and products involving sex, profanity and violence.

The two-tier rating system will categorize content offered directly by cell phone providers as either "Generally Accessible Carrier Content" or "Restricted Carrier Content."

The criteria for the ratings will be similar to those used by the movie, television, music and video game industries.

The announcement Tuesday by the industry group CTIA reiterated a pledge that the nation's leading wireless service providers would not offer any restricted content until they have provided controls for parents to block access to it by children.

That pledge has been seen as a sure sign that at least some wireless operators are mulling the potential riches that "restricted" services might generate. But it was unclear from the CTIA announcement how long it would take to develop the parental control technologies that would potentially usher in such services.

Two commissioners at the Federal Communications Commission applauded the industry's bid at self-regulation.

"This industry effort should really help families who rely on their cellphones but do not want their children inadvertently exposed to adult material," Commissioner Jonathan S. Adelstein said in a statement Tuesday.

Commissioner Kathleen Q. Abernathy said, "Although advanced technology provides new and improved opportunities to manage our lives and educate our children, in some instances it can also make the already-challenging job of parenting even more difficult. The voluntary initiative announced today by CTIA demonstrates that the wireless industry appreciates these challenges and is willing to better empower parents."