The American Society of Composers, Authors and Publishers (ASCAP) filed suit against AT&T asserting that ringtones qualify as a public performance under the Copyright Act. ASCAP, which has 350,000 members, collects royalties and licenses public performances of works under copyright.

The Electronic Frontier Foundation (EFF), however, asserts that copyright law exempts performances made "without any purpose of direct or indirect commercial advantage," which would include a ringtone heard in a restaurant.

The organization further argued that the move by ASCAP could jeopardize consumer rights and increase costs for consumers. The EFF filed an amicus brief for the case on Wednesday in U.S. District Court for the Southern District of New York. The Center for Democracy and Technology and Public Knowledge also joined the brief.

"These wrongheaded legal claims cast a shadow over innovators who are building gadgets that help consumers get the most from their copyright privileges," the EFF said in a blog post.

ASCAP's suit highlights efforts by the music industry to aggressively assert its influence in dealing with new digital media. ASCAP wants mobile operators to pay royalties or be held liable for the so-called public performances of the ringtones. The organization has indicated that it would not pursue claims against individual consumers but rather the operators.

Operators such as AT&T and others that sell ringtones already pay royalties to songwriters for use of their material. ASCAP rejects the argument that ringtones fall under the exemption and that performances can still infringe even if there is no commercial gain.

On June 12, ASCAP filed a document opposing a motion from AT&T asking for a summary judgment in the case, which the EFF has posted on its Web site.