In the days of dial up, everyone was familiar with the cacophony that was emitted from the modem as it was dialing up (if you need a reminder, listen here). I know that those sounds were all representations of what was happening in the modem while a connection was being negotiated. This infographic does a great job of explaining it:
My question is: why bother installing a speaker in every single modem and playing the connection negotiation every time? You could argue that it would help in diagnosing a problem, but then why leave the speaker connected and the volume turned up by default? Some modems had a volume knob, but others like this PCI modem didn't.
If it was just for diagnosing problems, surely a technician could have plugged in a speaker to a port on the modem and only listened to it when needed. As far as I know, all internet connection software like AOL showed a progress bar or animated status icon of some form to indicate that a connection was being established. Why add the speaker?