alt.hn

2/18/2026 at 1:43:25 PM

Show HN: Nedagram – Transfer Text Over Sound, when internet isn't available

by shayanbahal

2/18/2026 at 2:29:57 PM

Hello,

To send a simple text as "Hello" it takes 18 seconds which is excessively long.

There is a library called rattlegram which is well tested and would transmit the same data in less than half a second: https://github.com/aicodix/rattlegram

I'm developing with more people a platform called geogram, which basically looks into transmitting data with radios, bluetooth, wifi, USB-C cables or anything you have. We don't have modem over the phone yet. Maybe I can invite you to join so we can solve those obstacles together?

The website is https://geogram.radio

by nunobrito

2/18/2026 at 3:16:58 PM

This is so cool, thank you for sharing. I'm diving on the website and code and see what you got there. would be great to join and chat further about this.

RE Hello taking 18s, yes that is long, but one caveat is that with longer text it doesn't get longer linearly due to compression, the more repetition the better compression.

by shayanbahal

2/19/2026 at 10:08:36 PM

Let's talk on https://p2p.radio/chat/#development

Doesn't require credentials to chat there and we can talk about next steps, really enjoyed that concept of using normal phone calls again as modems.

by nunobrito

2/18/2026 at 1:45:34 PM

For those interested to know more and discuss the protocol, here's my attempt at documenting what worked at the end: https://github.com/shayanb/Nedagram/blob/main/docs/PROTOCOL....

I had to make sure the sound could be transferred on phone calls so it has lower baud rate than let's say dial up modems and many other methods (e.g. minimodem), I'd love to find a way to make it better.

Also got a suggestion to mix this with songs so it's less dodgy to play something like this on the phone. something that I want to look into as well.

by shayanbahal