Ringing phones don't violate performance copyright
... at least not in the US. Public performances of musical works are subject to copyright. That leads to things like copyright fees being payable when a hair salon or dentist plays a CD . The EFF reports that a US federal court ruled yesterday that "when a ringtone plays on a cellular telephone, even when that occurs in public, the user is exempt from copyright liability, and [the cellular carrier] is not liable either secondarily or directly". Seems that ASCAP wanted public performance royalties for ringtones.