Major U.S mobile operators will adopt a content rating system for video, music, pictures and games that they sell to their customers, reports PC World.

The Cellular Telecommunications and Internet Association (CTIA), which includes all the major U.S. mobile operators, unveiled the voluntary pledge on Tuesday. In the first phase of the commitment, the companies will classify the content they deliver in at least two categories -

1. Generally Accessible Carrier Content, to be available to all users.

2. Restricted Carrier Content, accessible only to users over 18 or with a parent or guardian's authorization.

Only items provided by carriers would be covered; content provided by end users or accessed via the public Internet would not be classified under those rules, according to guidelines published by the CTIA.