DTMF generating assistant
DTMF Generating assistant
DTMF signal detection/removal using adaptive filters
DTMF signal receiving apparatus equipped with a DTMF signal judg
DTMF signal receiving circuit
DTMF signal receiving system
DTMF tone detection
Dual hysteresis signal detection circuit
Dual signal triggered message waiting notification system for in
Dual tone detector operable in the presence of speech or backgro
Dual-tone multifrequency (DTMF) signalling transparency for low-
Dynamic ordering of an electronic phonebook