I don't know the technical specifics but I've had a Logitech and Sennheiser BT headset with dongle. I'm pretty sure the dongle is Bluetooth but it is definitely

I don't know the technical specifics but I've had a Logitech and Sennheiser BT headset with dongle. I'm pretty sure the dongle is Bluetooth but it is definitely doing something out of spec because there's a huge difference in quality between dongle and direct Bluetooth. And yea DECT is pretty nice. I also use it for gaming occasionally.