Audio

sudo apt install sox libsox-fmt-mp3 audacity ffmpeg

Tools

What	Link
Audacity	ubuntu apt tool
sox, libsox-fmt-mp3	ubuntu apt tool
DTMF tone decoder	http://dialabc.com/sound/detect/index.html

Check spectogram in Audacity.
You can create a spectrogram in sox as well:
```
sox Manon.mp3 -n spectrogram
```
produces