Dual-Tone Multi-Frequency (DTMF) signaling—commercially popularized as AT&T’s “Touch-Tone”—is the foundational ITU-T Q.23 standard protocol that translates keypad button presses into pairs of audible frequencies. Developed by Bell Labs in 1963, DTMF replaced the mechanical “clicks” of legacy rotary pulse dialing with a faster, machine-readable format that still powers interactive voice response (IVR) systems, telephone banking, and modern Voice over IP (VoIP) call centers today. 🎹 The Core Architecture: Why “Dual” Tone?
DTMF works by assigning eight distinct audio frequencies across a 4×4 grid matrix. When you press any key, the system simultaneously generates exactly two sinusoidal sound waves: one from a low-frequency group (representing the row) and one from a high-frequency group (representing the column).
What is Dual Tone Multi Frequency? Technology Guide – Sycurio
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