Ringback technology company Ring Plus sued U.S. wireless carrier Cingular in federal court Tuesday, although it wasn't immediately clear what patents the carrier was accused of infringing. The Beverly Hills, Calif. based Ring Plus said it was also planning litigation against the music industry as well, as the company would like to develop ringback technology as a marketing platform.

"The music industry, also possible targets for infringement litigation, already recognize ring tones and ringback tones as an effective means of promoting new and existing artists," the company said in a statement. "This ability to reach a widespread audience quickly is the appeal that advertisers everywhere are looking to capture." According to Ring Plus, if the so-called "ringback" tones are also used for advertising, as much as $14 billion stands to be made by 2011, far above the $2 billion currently projected.