The sound of dialup, pictured

Many of you will have seen this before, but it’s still a very nice bit of infographic work - with a 2500px annotated image, a spectrogram showing the handshake at the start of a (maybe) 21600bps connection.

Here’s a video highlighting each section as the audio plays (but too low-res to read the interesting annotations!):


Windytan’s site, in general, is a very interesting read. In a broad sense, “signal hacking”.