The dial-up modem sound comes from the handshake tones used when a computer connected to the internet through a telephone line. It was a normal part of home internet access throughout the 1990s and early 2000s, before broadband became standard. Online, the sound stuck around because it instantly communicates old technology, slow loading and awkward waiting. Creators still use it in memes and comedy edits whenever they want viewers to think of vintage internet culture or painfully outdated hardware.