> For the complete documentation index, see [llms.txt](https://cajac.gitbook.io/ctf-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cajac.gitbook.io/ctf-notes/misc/audio-processing/dtmf.md).

# DTMF

**Dual-tone multi-frequency** (DTMF) signaling is a [telecommunication signaling](https://en.wikipedia.org/wiki/Telecommunication_signaling) system using the voice-frequency band over telephone lines between [telephone](https://en.wikipedia.org/wiki/Telephone) equipment and other communications devices and [switching centers](https://en.wikipedia.org/wiki/Automatic_telephone_exchange).

## Resources

Detect DTMF Tones: <http://dialabc.com/sound/detect/>

DTMF Decoder: <https://dtmf.netlify.app/>

DTMF signaling - Wikipedia: <https://en.wikipedia.org/wiki/DTMF_signaling>