A digital mode decoding and terminal program that uses no terminal unit, terminal node controller, or multimode hardware. It does all its decoding using the sound card inside the computer, and it can interface with a radio using a COM port. Zakanaka is an extremely cost-effective way of operating PSK31 and RTTY.

G3LDI comments:
Quite a useful program for both modes. I have not used it in anger however nor for very long.