I did open the headphones to see that there was a battery in them; but didn't actually take them out and verify they are plugged in.So your radios should cut out and get quite when you talk. I used Racing Electronics kits for a while now. I prefer RE for both customer service and support but your mileage may vary. As said there is a 9V battery for the intercom function to work. Sorry I dont know anyone that uses the Racing Radios version. Most all my contacts use RE instead. They are the supported vendor for NASCAR as well as many other divisions.
When I did use mine, my scanner/radio would mute when I push the PTT. Voice from one headset would come out on another headset.
I have since switched to radio only headsets and no longer use the intercom function. For 99% of the fans the intercom function works very well.
Did you pull out the 9V battery and check it ?
If they ARE plugged in; and this is "as good as it gets" and won't cut off when I talk; I may just make them take them back and buy RE instead.
THANKS