Music on hold: Cisco's Opus Number One
https://www.youtube.com/watch?v=N7xn5zeJ4D4
https://en.wikipedia.org/wiki/Music_on_hold#Cisco's_Opus_Number_One
https://www.replicant.com/blog/the-surprising-roots-of-one-of-the-most-common-hold-music-songs/
