Yeah, acoustic modems ARE "old school", although it implies a different coupling into the phone system. I'm assuming you're talking about the "screeching" sound of them passing a carrier frequency, then the warbling screech as they "handshake" into synchronization. The ones most folks have actually heard had a speaker onboard as a sort of indicator. Same deal, except the speaker wasn't projecting into the mouthpiece of the phone's handset, it was just making noise so you knew it was alive and working before syncing up and shutting the speaker off to spare the humans the agony.
Modern modems communicate at much too high a frequency for human hearing.
I still don't get the connection to the tune you linked, but that's ok.