Fldigi

Software By W1HKJ & Associates
Fldigi is a modem program for most of the digital modes used by radio amateurs today: CW, PSK, MFSK, RTTY, Hell, DominoEX, Olivia, and Throb are all supported. It can help calibrate a sound card to a time signal and do frequency measurement tests.
Good software to receive digital modes, easy to configure and with updated database for cat control of the radio.