I set away from my desk all the time on conversations and never lose sound quality. It needs to be plugged into a USB port so as long as your phone system has the ability you are good to go!
You should be able to use any headset with Dragon. Just make sure you set the default input to the H600 in your sound controls. (And check the preferences for Dragon to see if you can change input devices there also. (
I have used this particular model for several years and the audio quality is as good as anything else that I've seen in the marketplace especially given the price of this unit. Also, this unit has a 10 to 15 foot range from the sensor where there is virtually no distortion in the audio.
I'm sorry but I can't answer that question. Mine is hooked up to my laptop through the USB. It's wireless. I supposed if your TV has a USB port it should work there also but it should be easy enough to try this if you buy it at the store. They should also be able to confirm.