DTMF Tone Generator & Decoder
Free DTMF tool for generating and decoding telephone keypad tones in your browser. Includes a 4×4 keypad with the A–D military row, sequence player with adjustable timing, microphone and audio-file decoder, multi-region call-progress tones, and WAV/MP3 export. Built for IVR developers, telecom engineers, ham radio operators, and post-production sound designers.
How to Use
Click keypad keys, paste a phone number into the sequence tab, or type 0–9 / * / # / A–D on your physical keyboard.
Adjust tone and pause duration with the sliders or pick the ITU Q.23 preset for compatibility with telecom equipment.
Open the Decoder tab, allow microphone access, or drop an audio file — the tool extracts the dialed digits with timestamps.
Save the sequence as WAV (8 kHz telephone or 44.1 kHz CD quality) or MP3 — ready for IVR uploads, audio editing, or film post-production.
Dial, decode, and export touch-tones with ITU-Q.23 precision
0-9 * # A-D · pause: , or space · long wait: w| # | Time | Key | Low Hz | High Hz | Confidence |
|---|---|---|---|---|---|
| Detected tones will appear here with timestamps | |||||
| Key | Precedence | Frequency |
|---|---|---|
| A | Flash Override | 697 + 1633 Hz |
| B | Flash | 770 + 1633 Hz |
| C | Immediate | 852 + 1633 Hz |
| D | Priority | 941 + 1633 Hz |
Features
FAQ
What is DTMF?
Dual-Tone Multi-Frequency — the touch-tone signaling each phone key emits as a pair of sine-wave frequencies (one low, one high). Standardized by ITU-T Q.23, used since the 1960s on Bell System Touch-Tone phones and now in IVR menus, modems, and ham radio autopatch.
What are the A, B, C, D keys?
The fourth column (1633 Hz) was used by US AUTOVON military telephones for call precedence — A = Flash Override, B = Flash, C = Immediate, D = Priority. Consumer phones omit them, but they remain part of the DTMF standard and are sometimes used by modern PBX systems for special routing.
Can I decode DTMF from a recording?
Yes — open the Decoder tab and either drop an audio file (WAV, MP3, OGG, M4A) or use your microphone live. The decoder outputs the decoded string plus per-tone timestamps, source frequencies, and a confidence score, exportable as CSV.
What is "twist"?
The amplitude difference (in dB) between the high and low tones. The ITU-T allows +4 dB / −8 dB. Many real telecom systems boost the high tone slightly to compensate for line attenuation — the slider lets you simulate that.
Why include historical Red/Blue Box tones?
For education, telecom history enthusiasts, and accurate film/TV post-production. These tones are legal to generate and study; transmitting them on live public phone networks is illegal in most jurisdictions.
What sample rate should I use?
8 kHz matches the bandwidth of the public telephone network — best for IVR uploads. 44.1 kHz is CD quality, 48 kHz is studio standard — best for film, video, and music production.
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