Cisco Unified Communications Manager hold music AKA Tim Carleton & Darrick Deel - Opus No. 1

Among the best known is the largely forgotten "Opus Number One" by Tim Carleton and high-school friend Darrick Deel, who 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.