To quote Alexis Madrigal from The Atlantic: “The noises our technologies make, as much as any music, are the soundtrack to an era.” And no sound is perhaps more iconic for the pre-2000 Internet, than the dial-up handshake. You can listen to it here, if you’ve never heard it. The image above (by Oona Räisänen) does a complete breakdown of what all that noise coming out of the modem actually means.
If you like this kind of stuff, head on over to the Museum of Endangered Sounds, a site that lets you listen to all the technological soundscapes of forgotten eras. Bonus Content: Dial-up handshake, slowed 700%. Very creepy.