For anyone that might be searching for a solution, I have been able to get HRD to take care of rig control and logging while also allowing VarAC to do it's thing; the configuration works quite well and leads me to believe there is no need for any other changes to either HRD or VarAC to facilitate this - just add-in an additional piece of software to the mix and have fun! The essential model for the below is described in this HRD knowledgebase/faq page: https://support.hamradiodeluxe.com/support/solutions/articles/51000052492-3rd-party-programs (https://support.hamradiodeluxe.com/support/solutions/articles/51000052492-3rd-party-programs) Steps: 1. Get VSPE or some other virtual serial port emulator software to create a pair of connected virtual serial ports (I used COM10 and COM11). I used VSPE from https://eterlogic.com/Products.VSPE.html (https://eterlogic.com/Products.VSPE.html) 2. Run HRD rig control and connect to your radio (my setup uses physical port COM1 for rig control). 3. Within HRD rig control, set up a port as shown in the HRD_Capture.png included below. 4. Image below: HRD rig control menu showing location of 3rd Party Serial Port menu item. 5. Within VarAC, setup frequency control via COM11 and use the same speed/parity/etc as for your physical radio connection/com port (for the KWD 570D it is 9600,8-N-2,HH Hopefully the snapshots below will be helpful / intelligible for anyone trying to replicate it on their own system. I hope it works for you, or gets you closer to a solution. VarAC is a ton of fun once you get it running! Image below: HRD, showing rig control menu item location Image below: HRD, showing configuration settings within HRD Image below: VSPE, starting point step of creation of 2 virtual paired serial ports Image below: VSPE, naming of the two paired serial ports Image below: VSPE, saving startup configuration for VSPE Image below: VarAC, showing my initial config settings (***I eventually suceeded with using VOX for PTT***) Image below: Reference, How to add an app to Windows startup sequence (put VSPE in startup)

Posting this here in hopes that it helps someone else solve a similar problem. My issue was: On a setup that was very well established for JT8, JS8, PSK31, etc, I was able to get everything working enough to be able to send out beacons and CQ's (only), but could not get any RF output once a connection was established. I went down many rabbit-holes trying to figure it out, but in the end it was very, very simple....the short answer is: go to Windows Sound Control Panel, select the device that is your Signalink OUTPUT (on my machine it was "5-USB AUDIO CODEC" on the PLAYBACK tab, right click on that device >> click Properties >> click the ADVANCED tab >> change the setting to "16-bit, 44100 Hz (CD-Quality)" >> OK >> OK Once I did the above, setting the sound output format to 44100 Hz on the SIGNALINK OUTPUT, I was able to transmit and make QSOs just fine. I hope this helps someone! 73 de KG9NI To get to Sound Control Panel on Windows 10: Press Windows + R keys together to launch the Run dialog box. Type mmsys.cpl and press Enter