Hi Thomas,
VARA HF and VARA FM are Windows programs that act as sound modems for HF and FM radios (respectively). They can be downloaded from
https://rosmodem.wordpress.com/. WoAD is able to connect to these programs via a TCP/IP connection. Some Winlink gateways support connections using VARA HF and/or FM.
The usefulness of this functionality within WoAD is dubious at best, as if you're running a Windows machine for the VARA sound modem, you could just run Winlink Express on the same box. I'm working on the assumption that at some point the VARA programs will be ported to run on Linux, Android, etc, where their usefulness, to WoAD at least, will improve greatly. And no changes should be required on WoAD's side as everything is done through a TCP/IP connection.
Hope that helps.
All the best,
Andrew
VA7YAA