Why did the dial up modem noise sound the same every time? What was the purpose of those sounds as the connection was being made?

Question

I understand that modems used the telephone line to transmit and decode sound into data, but I don’t understand why that noise everyone remembers needed to happen. You didn’t hear sound when you were loading a web page even though sound was being decoded by you modem… what was the purpose for it on start-up?

Edit: Autocorrect typo

In: Technology

Answer 1

The modems were testing the phone line, negotiating with the other modem on what protocols to use and how to work around noise on the lines. The sounds does sound very similar to us humans but to the modems even a small change in the pitch in one of the tones changes the meaning completely. And as the modems negotiate to higher and higher speeds it will sound more and more like static noise to us.