C3Subtitles: 30C3: My journey into FM-RDS
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My journey into FM-RDS

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Video duration
00:36:11
Language
English
Abstract
How I discovered mysterious hidden signals on a public radio channel and eventually found out their meaning through hardware hacking, reverse engineering and little cryptanalysis.

A story about my experiences with FM-RDS (Radio Data System), a digital subcarrier embedded in FM broadcast transmissions, and also cryptanalysis of the weakly encrypted TMC traffic messages contained therein.

I originally found about the existence of such transmissions in a roundabout way, by using a spectrum analyzer program to examine intermodulation distortion in my radio’s Line Out audio. As it turned out, the inaudibly quiet distortion, probably caused by the radio’s stereo demuxer circuitry, contained all the information needed to decode all RDS data present in the transmission. I will demonstrate the journey I took and give a short introduction to how the data is actually encoded. Live acquisition of local RDS data depending on signal conditions in the premises.

As a bonus, I'm introducing yet another little-known FM subcarrier called DARC, and my recent reverse engineering of the bus stop display radio protocol used in Helsinki.

Talk ID
5588
Event:
30C3
Day
2
Room
Saal G
Start
4 p.m.
Duration
01:00:00
Track
Hardware & Making
Type of
lecture
Speaker
Oona Räisänen

Talk & Speaker speed statistics

Very rough underestimation:
111.5 wpm
602.0 spm
107.4 wpm
580.0 spm
100.0% Checking done100.0%
0.0% Syncing done0.0%
0.0% Transcribing done0.0%
0.0% Nothing done yet0.0%

Talk & Speaker speed statistics with word clouds

Whole talk:
111.5 wpm
602.0 spm
Oona Räisänen:
107.4 wpm
580.0 spm