the NSA selector

the NSA selector is a eurorack module with two ethernet jacks and one audio output. any bit on the network will be sent to the audio output.

this is not an "audio interface". we do not play back any "format" such as RTP or MP3 or WAV or the like. the eurorack module does not "speak" any protocol. all traffic is forwarded from one network jack to the other unmodified. it's just tapped, intercepted to convert it to audio.

Photos

the tech bits

the NSA selector is a fast ethernet (FE=100Mbps) network switch with three ports. the two front ports are switched, and the third port is only available internally as 4 bit MII bus. it is configured as mirror port of the two front ports and wired to a 4 bit DAC and a low-pass-filter.

4 HP wide
55 mm deep
+12V : 100 mA
+5V : nothing
-12V : 2 mA
Switch chip: LAN9303
Config: 24LC64 I2C EEPROM

examples

watch the NSA selector video

sequencer script

in the folder sequencer/ you find a very simple shell script, that mimics a sequencer by network pings of different size.

plain image transfer

if we transfer uncompressed, unencrypted images e.g. in the .bmp format, we can hear the pixels.

encode audio to NSA's native format

the NSA selector's native format is 4 bits and 25 MS/s which originates from the typical PHY MAC interface called MII.

at first glance 4 bit audio appears to be really crappy, but we can use the ridiculously high sample rate. what we need is called a delta-sigma modulator.

other network traffic

be creative! online games, doomscrolling, network backup, IoT stuff, remote desktop protocols, or write your own code.

if possible disable encryption, then you can profit from not only timing pattern (of white noise), but also listen in on the plaintext payload. the NSA loves plaintext.

kit & assembly

available as assembled module or kit where you solder on the front plate.

watch the assembly video

Resources

Purchase

Lectronz store

Resources