system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why did dial-up internet make a noise when connecting?
gpt
The noises were the modems on each end “singing” to each other to determine the speed and settings on each end. One end would sing that its max speed was 56kbps and the other might reply 56kpbs, or 33.6kbps, or 28.8, and then they’d determine how fast to link up with each other so the connection was reliable.