You need an audio cable attached between the scanner and your MIC port on your sound card. Some use "line in". I have used both. I am a little confused by what your asking? Do you have both a PC mic and a soundcard mic ?
ADS-B decoder (Debian Pi) FlightAware Site #6076
Civilian and Military Aircraft Monitoring
396XT, 346XT, 890XLT, DSD+