Dial-Up Modem Sound | What Was That Dial-Up Internet Sound?
Dial Up Modem Handshake Sound - Spectrogram - YouTube
UZ7HO Sound-Modem update | Amateur Radio – PEØSAT
Museum of Portable Sound - The sounds of a dialup modem connecting to the internet are actually a language, and the sounds are a conversation between two 20th century-era machines. Listen along