Drew Burden

This tool uses audio and NOAA’s SAME protocol to encode and decode messages.

We’ve all heard the weird buzzing noise (or “digital burst”) on TV or radio when bad weather is around. (example) That’s not meant to annoy you; it’s a line of text. There are actually letters and numbers being transmitted. I’ve studied the protocol and developed something that will generate the corresponding digital burst for an arbitrary string of text.

WARNING: TECHNICAL INFORMATION FOLLOWS-
NOAA’s Specific Area Message Encoding (or SAME) protocol is used to further streamline the Emergency Alert System. Information about an emergency message (such as locations affected, type of message, where it’s coming from, and how long it will be considered effective) is transmitted in the form of digital bursts at the beginning and end of said message. These bursts are AFSK-modulated data with a throughput of 520.83 bits per second. Mark tone (binary 1) is 2083.3 Hz and space tone (binary 0) is 1562.5 Hz, with each tone lasting about 1920 microseconds. Bytes are transmitted in reverse order (LSB -> MSB), that is,  00010111 would be transmitted as 11101000. There are other technical specifications regarding its use in the real world, but it’s irrelevant here. Essentially, if you handed the right text to it, I have a SAME encoder. It outputs true SAME-encoded data.

Update: The very first web version of this program did not output true SAME-encoded data. I conveniently forgot to write in the byte reversing. I have updated both the encoder and decoder to follow the protocol, so any files you may have encoded on or before October 11, 2006 will not decode correctly.

To decode a message, upload an encoded WAV file. The original message will be displayed to you. This will only work if you used this tool to create the WAV file.

If you don’t believe that this is an actual sound file you’re getting, listen to the WAV file when you download it. It may be a bit loud, so be sure to turn down your volume.

Encode some text! (To decode a previously-encoded sound file, click here)

If you have any comments or suggestions, please send email to drew@drewburden.com.