Bell, in inventing the telephone, made what was effectively a mirror-image miscalculation: He envisioned one of the primary uses for the telephone to be as a medium for sharing live music. An orchestra or singer would sit on one end of the line, and listeners would sit back and enjoy the sound through the telephone speaker on the other. So, the two legendary inventors had it exactly reversed: people ended up using the phonograph to listen to music and using the telephone to communicate with friends.
