system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 these 2 questions. How does/did dial up internet work? Why and how did making a phone call affect the internet connection?
gpt
It was literally like making a phone call. One computer to another.

The sender would convert 1’s and 0’s into ‘analogue noise’ as if talking and the computer at the other end would covert them back into 1’s and 0’s again.

You can only make one phone call at a time.

If you picked up the phone while an internet call was in place. The background noise from the phone mic added to conversation. Therefore this would confuse a computer when listening as it failed to understand the extra noise. So it would freak out and disconnect.

History: the first modems; you had to place a phone handset onto a ‘mic and speaker’ and manually dial a phone number on the phone for the computer.