Why did dial-up modems make sound in the first place?

Question

Everyone of an age remembers the distinctive dial-up modem sounds but why were they audible to begin with?

In: Technology

Answer 1

Here’s a video of the sound actually being made

[https://www.youtube.com/watch?v=FG1AQcGGSec](https://www.youtube.com/watch?v=FG1AQcGGSec)