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Show HN: TCP/UDP over sound

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Re: Show HN: TCP/UDP over sound

#11
post #9

GMSK [1] among others. Pretty cool! [1] https://en.wikipedia.org/wiki/Minimum-shift_keying#Gaussian_...

If anyone is curious about the modulation and error correction techniques supported by this modem, you can try out https://quiet.github.io/quiet-profile-lab/ in your browser, which uses Web Audio to interact with your sound card. This runs at a frame level, about one layer below the UDP/TCP provided by quiet-lwip, but all of the modem characteristics are the same.

Re: Show HN: TCP/UDP over sound

#12
post #3

Clever, an audio soft-modem. Was there a reason to not implement this as an actual modem with a frequency band assigned to either channel and then to run SLIP or PPP over it?

The goal of this library is to provide the familiar sockets interface over a non-traditional eth, in this case sound. Can you expand on your question? I think I understand what you're saying but I don't quite see what it would accomplish. And this is an "actual" modem, whatever that means. If you mean an IETF/RFC modem spec, there are many reasons. Those specs are focused on narrowband POTS limitations, which we don'…

   > over a non-traditional eth,
   > in this case sound
Sound is a non-traditional way of moving data?!

Re: Show HN: TCP/UDP over sound

#14
This is exceedingly cool.

If someone wants to play with lower bandwidth data (text, basic file transfer) over sound, it's a pretty active area in the world of amateur radio. You can download the open-source program fldigi (http://www.w1hkj.com/modes/index.htm) on 2 computers, point speakers and microphones at each other, and try sending text (or files/images). The "flmsg" program will send pre-formatted stanzas which get converted into standard forms.

That being said, doing things like TCP/IP and other data is rather difficult on radio, mainly due to the duplex requirements and frequency spacing. But in pure audio, much more possible.

Re: Show HN: TCP/UDP over sound

#15

Earlier quoted context omitted.

The goal of this library is to provide the familiar sockets interface over a non-traditional eth, in this case sound. Can you expand on your question? I think I understand what you're saying but I don't quite see what it would accomplish. And this is an "actual" modem, whatever that means. If you mean an IETF/RFC modem spec, there are many reasons. Those specs are focused on narrowband POTS limitations, which we don'…

> over a non-traditional eth, > in this case sound Sound is a non-traditional way of moving data?!

Non-traditional in the sense that I can't immediately transport data over my sound card with

Re: Show HN: TCP/UDP over sound

#16

Earlier quoted context omitted.

Ah, yeah, that makes sense. My plans for this library are mostly focused on using the sockets directly, with the library linked by both peers. I'm really interested in being able to use this as a simple UDP client/server.

You'd get that just about for free by running SLIP or PPP over your audio modem.

Perhaps - my plan is to use this on iOS and Android where I suspect SLIP and PPP interop is not as straightforward. By bundling everything in with the app, there won't be any kernel dependencies, aside from the sound card.

Re: Show HN: TCP/UDP over sound

#17

Earlier quoted context omitted.

> over a non-traditional eth, > in this case sound Sound is a non-traditional way of moving data?!

Non-traditional in the sense that I can't immediately transport data over my sound card with

If you install a software modem ... you can?

Re: Show HN: TCP/UDP over sound

#18
post #14

This is exceedingly cool. If someone wants to play with lower bandwidth data (text, basic file transfer) over sound, it's a pretty active area in the world of amateur radio. You can download the open-source program fldigi ( http://www.w1hkj.com/modes/index.htm ) on 2 computers, point speakers and microphones at each other, and try sending text (or files/images). The "flmsg" program will send pre-formatted stanzas whi…

This is an interesting point. And in fact, the mechanisms that libquiet uses to encode/decode come from liquid dsp, which is in fact intended for use over RF.

Re: Show HN: TCP/UDP over sound

#19
I look forward to the inevitable HN 'What is this thing?' post in ten years when somebody implements this in a one-off system then leaves the company. "Here is a recording of the two devices talking, one in the left channel and the other in the right. Can we figure out what they're saying?"
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