DTMF Tone Generator
DTMF stands for "Dual-Tone Multi-Frequency": it's the technology used for tone-based telephone dialing. Each key emits a unique combination of two frequencies. This tool plays a single key, lets you compose a full sequence, or download all keys as a ZIP.
Listen to a key
Export format
Format of the generated WAV files (sequence and ZIP). Does not affect live key playback.
Compose a sequence
Enter a sequence (digits, * and # only). Other characters are ignored.
Use cases
- IVR or answering machine testing (auto-dial).
- Retro sound design: films, nostalgic games, arcade machines.
- Educational demo: illustrate the DTMF principle in telecom courses.
- Reverse engineering: test a homemade DTMF decoder.
- Sound effects: ringtones, transitions, phone jingles.
FAQ
How long must a tone be to be recognized?
ITU recommends at least 40 ms per tone. In practice, many decoders require 65–80 ms for reliable detection, with at least a 40 ms gap between tones.
Which frequencies are used?
Each key combines a low frequency (697, 770, 852 or 941 Hz) and a high frequency (1209, 1336 or 1477 Hz). The 4×3 grid covers the 12 standard keypad keys.
What are these files good for?
Testing answering machines and IVR systems, retro sound design, demos, educational telecom projects.
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