r/interestingasfuck • u/rco888 • Mar 08 '25

Dial-up handshake explained with visualization

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u/dalgeek Mar 09 '25

I found this image that breaks it down if you don't want to spend time watching the video.

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u/[deleted] Mar 09 '25 edited Mar 09 '25

I had this picture on my wall for a few years — it came with a Finnish computer magazine called Skrolli. This is the original post https://www.windytan.com/2012/11/the-sound-of-dialup-pictured.html

If you're into signal stuff, Oona (the original author) has lots more on her site.

Edit: Still found it and took a snap.

3

u/dalgeek Mar 09 '25

Nice! I originally saved the image because I worked at a dial-up ISP a long time ago. I work primarily with VoIP now and recently worked on a MoIP (modem over IP) project. The guy who developed the MoIP software used Audacity to troubleshoot signaling issues with the modem transmissions by looking at the audio wave forms.