Qtmm is a simple AFSK1200 decoder that uses the computer’s sound card for input. It can be used to decode packet radio, APRS and telemetry from OSCAR and Cubesats.
Testing shows a good performance in monitoring the International space station APRS Beacon. More @ Qtmm soundcard modem for decoding AFSK1200

Telemetry reception from the AO-27 amateur radio satellite, which also uses AFSK.