Patent ID: 8311033

Claim:
A DTMF (Dual-Tone Multi-Frequency) tone signal transmission method executed in a system comprising first and second IP (Internet Protocol) telephone terminals, and a proxy connected to the first and second IP telephone terminals utilizing IP communication, the method comprising: transmitting a request to generate a digitized and packetized DTMF tone signal from the first IP telephone terminal to the proxy by using the IP communication in order to send the digitized and packetized DTMF tone signal to the second IP telephone terminal; receiving the request to generate the digitized and packetized DTMF tone signal at the proxy; generating at the proxy an original DTMF tone signal based on the request to generate the digitized and packetized DTMF tone signal; converting the original DTMF tone signal with a voice codec at the proxy making the original DTMF tone signal to become an DTMF tone signal represented by a codec signal; putting the DTMF tone signal represented by a codec signal in an RTP (Real-time Transport Protocol) packet at the proxy; and transmitting the RTP packet from the proxy to the second IP telephone terminal by using the IP communication, wherein the proxy decodes a voice signal from the first IP telephone terminal, adds the original DTMF tone signal to the decoded voice signal, and converts the original DTMF tone signal added with the decoded voice signal with the voice codec at the proxy making the original DTMF tone signal added with the decoded voice signal to become represented by a codec signal.