Telephony
DTMFDTMF
Also called: touch-tone · keypad tones
DTMF (Dual-Tone Multi-Frequency) is the set of tones a telephone keypad produces when keys are pressed — the 'touch-tone' signals. Voice agents use DTMF to let callers enter digits like account numbers, PINs or menu choices reliably.
DTMF is useful when spoken input is risky or private — entering a numeric ID or a payment digit by keypad is more accurate and more secure than speaking it aloud on a recorded line.
Related terms
Interactive voice responseThe classic 'press 1 for sales' phone menu system. IVR is menu-driven and can't understand free speech — the predecessor to conversational voice AI.VoIPVoice over Internet Protocol — carrying phone calls over the internet instead of traditional phone lines. The transport layer under most modern voice agents.Call routingDirecting an incoming call to the right destination — person, team, or queue — based on rules, caller input, or what the AI agent understands.
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