Patent ID: 7423983

Claim:
A signal processing system, comprising: a voice exchange for exchanging voice signals between a first telephony device and a packet based network; a full duplex data exchange for exchanging data signals from a second telephony device with demodulated data signals from the packet based network, wherein the full duplex data exchange demodulates data signals from the second telephony device, outputs the demodulated data signals to the packet based network, remodulates demodulated data signals from the packet based network, and outputs the remodulated data signals to the second telephony device; a pitch period estimator for estimating a pitch period of a voice band signal from one or both of the first and second telephony devices, using an autocorrelation function; signal power measurement circuitry for producing at least one measurement of power of the voiceband signal from one or both of the first and second telephony devices; and a call discriminator for selectively enabling at least one of the voice exchange and the data exchange based at least upon a comparison of the pitch period estimate and a plurality of thresholds, and the at least one measurement of power of the voiceband signal.