You actually don't need to tell HUB about the Target Softphone for that error that comes up.
In the RingCentral Phone application go into Settings > Sound and make sure your microphone and speakers (and ringer too, if that's what you prefer) are set to the Voyager direct (not "Same as System"). Also make sure the Plantronics headset option is turned on (blue).
If that doesn't help, I
think that your issue might be that the headpiece is losing connection with the computer (going to sleep?), but once it reconnects/wakes up it should figure itself out and re-enable the setting above.
Thanks Nicole, switching from "Same as System" now and will give it a go.
I use Plantrionics Hub and have my 'target softphone' set to 'None' and just changed the sound settings as Nicole has said - works well for me.
I have applied the setting recommended above however I still randomly get "Plantronics Device Controls Disabled"...of course right when I'm trying to answer a call. When I go to Settings - General and slide the "Plantronics headset" slider off and then back on I can't, I get the "...Controls Disabled" again. I have to fully close both RingCentral Desktop App and Plantronics Hub down and restart before the slider will re-engage. Any thoughts???