20 bits = 2 and a half bytes, and you are right that is enough.
What surprises me is how people regarding this as "novel" not too long ago quite a few people used a "modem". That was a mythical device that used phone networks to transmit information. Regular phones would pick up that as sound.
Sure there are few technical hurdles - covert communication and stringent error correction are most visible, but concepts are remarkably similar.
It's surprising how many people either forget about modems or never had internet in the days of modems. I've had numerous nerdy conversations and theory crafting scenarios where someone will bring up the crazy idea of using sound to transmit data. I'm just like "Yeah, we've done that already. Remember dialup?".
Also, modems didn't really seem very different from ethernet. My initial reaction as an early adolescent to first encountering ethernet was along the lines of, "oh, so it's just a wider port? what's all the fuss about?" Besides all the funny noises on connection (which, as an aside - why did the handshake have to actually be audible?), everything seemed to work the same, just more slowly. You don't have to forget about modems to be unaware that using sound to transmit computer data was once common.
Generally the handshake was audible so that you could tell if someone was already on the phone when you started connecting, or if someone answered the phone instead of a computer.
>It's surprising how many people either forget about modems or never had internet in the days of modems.
Pardon the snark, but what is surprising about that? Every person with access to the internet born since about 1997* will have no memory of using dialup. The ratio of people who used dialup relative to the people on the internet is going to continue to dwindle rapidly from here on out. Even then, I probably spent 6 or 7 years dialing up, and the connection of that to this story never happened in my brain.
* say 2003-2004 was when broadband went mainstream, at that point, people born in 1997 will be 6-7 years old.
Yeah situations I've described. I didn't really give much background information.
IE: I was having a conversation with some techie friends back when the SOPA scare was still at its peak. We were discussing purely hypothetical doomsday scenarios that would involve a "darknet" and the technical implications of creating an entirely subversive network. The idea was brought up that we could use our existing telephone infrastructure to send data, and only a way to transfer data via sound would need to be developed. This was shared amongst a few of the participants until I piped up and said "you know dialup has done this already, right? The information is already there."
This is a conversation amongst people who are involved with and passionate about technology and are around my age or older. These are the kinds of people that I'd expect, if not to think of specifics right away, but to at least be lead to something that was as pervasive as dialup. True, I don't expect an 18y/o of today to know or think about it, or even a 20y/o, but a 25+ hacker, developer, or general tech geek? I'm just surprised at how many in that former category just don't remember it.
Smartmodems of the 1980s didn't use sound to transmit data, they modulated an electrical signal directly on the line. They were silent (except during call set up, but that was just a "Monster Rancher" to confirm set up was proceeding in the normal way)
Beyond modems, there are also some obscure biological machines that transmit information by modulating sound waves in the air that have been around for some millions of years.
What surprises me is how people regarding this as "novel" not too long ago quite a few people used a "modem". That was a mythical device that used phone networks to transmit information. Regular phones would pick up that as sound.
Sure there are few technical hurdles - covert communication and stringent error correction are most visible, but concepts are remarkably similar.