V.90 modem handshake diagram

[pne]

The Sound of the Dialup: an Example Handshake by Oona Räisänen (2500×1301px JPEG, cc-by-sa 3.0)

via dotaturls

A fascinating, annotated image of what a modem handshake (V.90, apparently) looks like when split up into frequences (is that called a spectrogram?), and what the individual bits mean.

A pity that my modem days were so long ago that I don’t really recall what the handshake sounded like; it would have been even more fun to correlate the sound I heard with the visual description in that image.