If they were chatting about digital modes like PSK, MFSK,
You can use the sound card and a simple interface, one cable to the audio output of your rig to your soundcard and a cable with audio pad 10 K to 1 K from the soundcard to the audio input to the rig, then a transitor "switch" for PTT on the com port.
See:
http://www.waypoint.com/users/~discobay/manual.htmHas links to free software. If it is Packet then that is a different program called AGWPE and a terminal program is needed.
HTH