I remember reading this when it came out, and it was fascinating, especially considering listening to modems to diagnose problems is how I made my bones in tech

I remember reading this when it came out, and it was fascinating, especially considering listening to modems to diagnose problems is how I made my bones in tech support back when CompuServe was still a thing. I'm an old timer, and have even used a 300 baud modem with an acoustic coupler that the article referred to. I listened to the evolution of modem handshakes, and had no idea what parts meant what, but over the years I correlated different problems to different sounds, and through osmosis learned the various AT commands for different chip manufacturers (the main three I ran across were Hayes/Rockwell, USR, and Motorola) to lock them in certain modes - set the flow control mode (RTS/CTS or X-on/X-off), set the max and min baud rates, and set various error control algorithm modes. Doing tech support for a couple years in the 90s, the biggest problem I saw (beyond the fact that average users were pretty unsophisticated back then), was the quality of telephone lines in certain areas of the country. If you live in the sticks, you're screwed and lucky to achieve 9600 baud with any consistency. If you live in larger cities with crumbling infrastructure, you're likely to have some "signal bleed" (not sure what to call it) where other conversations are faintly audible on your lines. In both of these cases, the negotiation sequence would restart several times, sometimes getting lucky and connecting, but more often failing until we found the right AT commands to lock a lower baud rate and force error correction - MNP? I think that was the magic bullet in most cases. In the end, the phone infrastructure improved greatly just about everywhere, but by then it didn't matter as much, as people started moving to cable modems, typically plugged directly into a desktop computer, running Win 95 and getting hijacked by 0 day exploits to build the first botnets. Good times. Anyway, I'm glad to see this article has held up over time and people still find it interesting.