Fldigi is a modem program which supports most of the digital modes used by
ham radio operators today. You can also use the program for calibrating your
sound card to WWV or doing a frequency measurement test. The program also comes
with a CW decoder. fldigi is written with the help of the Fast Light Toolkit X
GUI. Fldigi is a fast moving project many added features with each update.
Flarq (Fast Light Automatic Repeat Request) is a file transfer application
that is based on the ARQ specification developed by Paul Schmidt, K9PS.
It is capable of transmitting and receiving frames of ARQ data via fldigi.