Disclosure: This post contains affiliate links, including a link to Vapi. If you click through and sign up for a paid plan, I may earn a commission at no extra cost to you. I only recommend platforms I have personally evaluated. Full affiliate disclosure here. Home › SIP Telephony › How Voice AI handles DTMF: the complete guide SIP Explainer How Voice AI handles DTMF: the complete guide P Priyanka Senior Voice AI PM  ·  April 14, 2026  ·  10 min read  ·  1,900 words SIP telephony Voice AI DTMF The short answer DTMF - the tones generated when a caller presses keys on their phone - can be transmitted in three different ways over a SIP connection, and Voice AI systems need to be configured for the right one. The wrong DTMF mode means keypad presses are silently ignored - the caller hears nothing, the AI receives nothing, and the interaction fails without a visible erro...