GAO's Dual Tone Multi-Frequency (DTMF) Software is an implementation of a Dual-Tone Multi-Frequency (DTMF) generator and decoder. DTMF is an international signaling standard for touch-tone telephones. The DTMF generator generates standard telephone digits as the sum of sinusoids corresponding to a frequency table for each digit. The DTMF decoder will take a digital signal as input and produce the decoded digit. GAO's DTMF software generates and decodes 8 kHz PCM samples.
DTMF has a variety of uses in telephone systems. It is widely used in interactive control applications such as telephone banking, electronic mail systems, and many other menu-driven operations that respond to digits entered from a telephone. GAO DTMF generator and decoder consists of four user-callable functions that perform the generating, decoding, and initialization operations.
For a complete list of GAO's Telephony Software products, please see GAO's Telephony Software.