Load reduction methods for DTMF decoders with adaptive omission of frequency analysis

Dual-Tone Multi-Frequency (DTMF) signaling is used in telecommunication systems for dialing telephone numbers and sending commands to equipment such as interactive voice response (IVR) systems. There are two types of signalings to transmit DTMF digits: in-band and out-of-band. Since many systems use in-band signaling, equipment that uses DTMF signaling needs to support in-band signaling. Media servers that provide IVR services must process a huge number of sessions in parallel. The load of decoding in-band DTMF digits needs to be reduced to increase in the number of sessions processed by media servers. This paper presents load reduction methods with adaptive omission of frequency analysis and simulation results showing that the presented methods reduced the load of DTMF decoding by more than 50%.