Why did the dial up modem noise sound the same every time? What was the purpose of those sounds as the connection was being made?

Question

I understand that modems used the telephone line to transmit and decode sound into data, but I don’t understand why that noise everyone remembers needed to happen. You didn’t hear sound when you were loading a web page even though sound was being decoded by you modem… what was the purpose for it on start-up?

Edit: Autocorrect typo

In: Technology

Answer 1

It’s because there were a lot of different speeds of modems, based on the capability of the modem itself and how good the connection was.

Think of it like someone who can speak many languages calling in to a customer service line. He’d probably start with the language he’d assume is used: “Hi, this is Mr. Polyglot, my printer stopped working.”

If he hears a “uh…” on the other side: ok! Not English; he needs a different protocol for them to understand him.

“Sprechen Sie Deutsch?” “…”

“Habla Espanol?” “…”

“Nihongo wa hanasemasu ka” “Hai! Nihongo desu!”

Protocol established! They speak Japanese! Now Mr. Polyglot knows he will need to speak Japanese in order for them to understand his question and send an answer.

The connection matters as well. It doesn’t matter if you can send and receive data super fast if most of it is garbled by the time it gets there! If Mr. Polyglot has a bad connection, even if he is speaking the language they understand — the right protocols to connect — half or more of what they say to each other is garbled. So, during that first exchange of greeting and response, they’ve also figured out how slowly they need to talk to help the other person understand.

Good connection? Both people can talk fast (if they can). Bad connection? They will probably slow down and talk more carefully so they don’t have to repeat everything fourteen times.

The noises you hear are basically: HI! I’m a 56.6K modem! …you’re not? Hi! I’m also a 28.8K modem! Great, you are too! Crap, our telephone connection sucks, though, how about we drop to 14.4K … testing…. testing… now you hear me fine? Great! Ok, here’s what I wanted….

It was audible back then as a way to troubleshoot what was going on. As rarely as that was used. Not sure I ever knew anyone who did.