hello, I need to make a dtmf decoder using java. And it has to be decoded using the pc sound card. Right now all i can do is connect 2 phones through my modem. Any suggestions on how do i map the modem sound onto my pc sound card? My modem does not have a connection for a jumper. So i need to know how can i do it without a jumper. Secondly.. Which algorihtm is preferable? Using FFT or Goertzel algorithm? im totally new to DSP. So i waould appreciate any detailed help.