IP電話
Among the best known is "Opus Number One", largely forgotten by Tim Carleton and high-school friend Darrick Deel, the teenagers that recorded it on a four-track tape recorder in 1989. Deel went on to work for Cisco in building the company's first VoIP phone. When a need for default on hold music came up, he recalled the track he and Carleton had recorded and reached out to Carleton for approval.