Patent ID: 6035179
Filing Date: 2000-03-07
Classification: H04M,H04Q,H04W

Abstract:
A method for transmitting DTMF signals over the radio path in a digital mobile telephone system, wherein the following steps are taken at the transmitting end,establishing, from an incoming signal, speech frames containing speech parameters during active speech and comfort noise frames containing background noise parameters during pauses,detecting, in detection periods, a DTMF signal possibly included in the incoming signal and establishing modified comfort noise frames, each of which contains both a DTMF identifier and DTMF frequency pair information in addition to comfort noise information, characterized byadding individual linking information to each successive modified comfort noise frame relating to the same DTMF signal, said individual linking information indicating the duration of the DTMF signal from the first detection time period of the first modified comfort noise frame to the frame concerned, including said frame,transmitting the established modified comfort noise frames as channel coded to the radio path.