VarAC is a relatively new digital mode, which allows for fast text based QSO's. This mode makes use of the VARA-HF digital modem software used by WinLink. It is very fast and virtually error free, even in poor conditions.
An Israeli ham, Irad Deutsch, 4X1AC, has written a chat application, VarAC, that uses the VARA-HF software modem.
VarAC is a great mode for keyboard QSO's--fast and error free. The software is beta and Irad is always looking for suggestions for new features or improvements.
Larry, W1IZZ