What you’re hearing is the way 20th century technology tunneled
through a 19th century network; what you’re hearing is how a
network designed to send the noises made by your muscles as they
pushed around air came to transmit anything, or the
almost-anything that can be coded in 0s and 1s.
If you’re of a certain age, the sound of a dial-up modem initiating a connection will forever trigger a Pavlovian response.