# DTMF Tone Generator

Generate ITU-T Q.23/Q.24-compliant DTMF touch-tone sequences (0-9, *, #, A-D) as audio files — IVR prompts, PBX testing, film props, decoder development. Tone/pause timing, twist and level configurable, Q.24 compliance checked.

> Canonical page: https://elysiatools.com/en/tools/audio-dtmf-tone-generator

- **Category:** Media

- **Keywords:** dtmf, touch tone, dual tone multi frequency, ivr prompt, telephone tones, keypad audio, q.23

## Overview

Dual-Tone Multi-Frequency signaling uses one low-group (697/770/852/941 Hz) and one high-group (1209/1336/1477/1633 Hz) sine per key, per ITU-T Q.23. This generator synthesizes any keypad sequence with exact per-digit timing and encodes it to WAV, MP3, FLAC, M4A or OGG. Defaults follow the Q.24 receiver recommendations: tone ≥ 40 ms (default 90 ms), pause ≥ 40 ms (default 60 ms), signalling velocity ≤ 10 digits/s, and twist — the high-group power relative to the low group — kept inside the −8…+4 dB acceptance window. Every tone edge gets a 5 ms raised-cosine ramp so clips never click while the mark duration stays compliant. A compliance flag reports whether your exact settings would be detected by a Q.24-conformant receiver. Output at 8 kHz for telephone-authentic audio or 44.1 kHz for studio use; repeat the whole sequence up to 10× for loop testing.

## Inputs

- **Digit sequence (0-9 * # A-D)** (text): e.g. 1705551234 or 123A#*0D
- **Tone duration (ms)** (number)
- **Pause duration (ms)** (number)
- **Twist (high group rel. low, dB)** (number)
- **Level per tone (dBFS)** (number)
- **Sample rate** (select)
- **Output format** (select)
- **Repeat sequence** (number)

## When to use

- Testing PBX switches, VoIP gateways, and IVR routing trees with repeatable dialed numbers.
- Benchmarking DTMF decoder algorithms against variable twist, short mark intervals, or low signal levels.
- Producing telephone dialing sound effects and touch-tone audio props for film, theater, or podcast production.

## How it works

- Enter a digit sequence using valid DTMF characters (0-9, *, #, A-D) and choose mark and pause lengths in milliseconds.
- Adjust tone twist to simulate frequency attenuation, set output level in dBFS, and select either an 8 kHz telephony or 44.1 kHz studio sample rate.
- Synthesize the dual-sine audio waveform with smooth 5 ms raised-cosine edge ramps to prevent transient clicks, while automatically verifying ITU-T Q.24 compliance.
- Export the generated tone burst sequence directly to your preferred audio container (WAV, MP3, FLAC, M4A, or OGG).

## Use cases

- VoIP and IVR Quality Assurance: Feed controlled DTMF bursts into SIP trunks to test digit recognition and timeout handling.
- Firmware and Hardware Decoder Testing: Generate edge-case sequences with negative twist and minimum duration to validate DSP tone-detector reliability.
- Film Sound Design: Generate clean, artifact-free telephone keypad dial cues encoded at broadcast-standard sample rates.

## Frequently asked questions

### What frequencies are synthesized for each DTMF digit?

Per ITU-T Q.23, each key combines one low-group tone (697, 770, 852, or 941 Hz) and one high-group tone (1209, 1336, 1477, or 1633 Hz).

### What is twist in DTMF signaling?

Twist measures the power difference in decibels between the high-frequency and low-frequency tone groups, within a standard acceptance window of −8 dB to +4 dB.

### Why include a 5 ms raised-cosine ramp on tone edges?

The ramp rounds the leading and trailing edges of each tone burst to eliminate audible switching clicks without violating minimum detection duration.

### When should I select 8 kHz instead of 44.1 kHz?

Select 8 kHz to simulate standard G.711 narrow-band telephony audio, and use 44.1 kHz for broadcast, podcasting, or general multimedia playback.

### Are the military and routing tones A, B, C, and D supported?

Yes, letters A through D represent the fourth-column high-frequency tone (1633 Hz) paired across each of the four standard low-frequency tones.

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- [DTMF Decoder](https://elysiatools.com/en/tools/audio-dtmf-decoder): Detect DTMF touch-tone digits in any recording and recover the keypad sequence with timestamps. Goertzel filter bank per ITU-T Q.23/Q.24 — measures both tone frequencies, twist and duration for every keypress.
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## Samples

- [Copyright-Free FLAC Audio Samples](https://elysiatools.com/en/samples/flac-samples): Lossless FLAC audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
- [Copyright-Free MP3 Audio Samples](https://elysiatools.com/en/samples/mp3-samples): Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio
- [Copyright-Free WAV Audio Samples](https://elysiatools.com/en/samples/wav-samples): Uncompressed PCM WAV audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
- [Copyright-Free Raw PCM Audio Samples](https://elysiatools.com/en/samples/pcm-samples): Raw PCM s16le audio samples featuring nature ambience and relaxing music for waveform, playback, and conversion workflows