What does DTMF mean?

DTMF explained: what dual-tone multi-frequency means and how key tones are transmitted with sipgate.

DTMF means Dual-Tone Multi-Frequency (dual-tone multi-frequency). In simpler terms, these are keypad tones.

When do I need DTMF?

When calling a voice computer, which requires input via keypad tone, this is done via DTMF. In addition, DTMF is used when calling the sipgate voicemail is used, because it asks for a PIN via keypad tone. But DTMF is also needed for various telephony features such as holding and transferring you need DTMF.