# What is DTMF?

> DTMF (Dual-Tone Multi-Frequency) is the signaling produced when a caller presses a phone keypad — each digit is a pair of audio tones the network decodes. It is how callers navigate IVR menus ('press 1 for sales') and enter data like account numbers or a voice-OTP confirmation. In VoIP, DTMF is commonly sent out-of-band (RFC 2833 / telephone-event) rather than as in-band audio, so it survives compression. See /answers/what-is-ivr and /answers/programmable-voice.

- Canonical URL: https://www.broadnet.me/answers/what-is-dtmf
- Language: en
- Last reviewed: 2026-07-22
- Publisher: BroadNet (https://www.broadnet.me)

## Related

- [All answers](https://www.broadnet.me/answers)
- [Glossary](https://www.broadnet.me/answers)
- [What is IVR (Interactive Voice Response)?](https://www.broadnet.me/answers/what-is-ivr)
- [How does programmable voice work?](https://www.broadnet.me/answers/programmable-voice)
- [How does conversational AI for voice work?](https://www.broadnet.me/answers/conversational-ai-voice)
- [What is SIP (Session Initiation Protocol)?](https://www.broadnet.me/answers/what-is-sip)
- [Voice](https://www.broadnet.me/products/voice)
- [Voice integration](https://www.broadnet.me/products/voice)