This Bluetooth connection on the handset is intended to sync to a cell phone, presumably to be able to use the handset to make cell phone calls. It will not, however, connect to Bluetooth devices like our headsets.
Note: You may be able to connect it, and even see DECT Headset in the menu, but we cannot actually use them together.
If confused, then think of this Bluetooth handset like Beats headphones or Airpods. Our Leitner Bluetooth (and any of our other Bluetooth headsets) cannot connect to other headsets, and only to the root Bluetooth device, which would be cell phones or computers (and in rare instances, phone bases).
Too bad, too :(