What was the original goal of the harmonic telegraph?

Answer

To send multiple telegraph messages simultaneously over a single wire

The harmonic telegraph was designed to modulate various musical tones over telegraph wires at the same time, which would allow for an increase in the speed and capacity of electrical communication. While working on this specific challenge of transmitting simultaneous tones, Bell realized how to apply these mechanisms to the transmission of the human voice.

What was the original goal of the harmonic telegraph?
inventionAlexander Graham BellinventorMotivation