Using the Bluetooth voice compatibility mode setting from the hidden menu on Konftel 55Wx can in many cases solve issues in Windows. Access it by going to Settings (cogwheel) and longpressing on the System button for 4-5 seconds on Konftel 55Wx. Enable Bluetooth voice compatibility mode.
Konftel 55Wx works best when connected over USB to a PC, since this will also charge the unit and has the most stable connection. Bluetooth functionality is mainly to be used when connecting to mobile phones (which works really good). The reason why we recommend USB over Bluetooth for PC is poor compatibility in both Bluetooth hardware and software in Windows OS, especially when connecting to Bluetooth headset.
We have realized that we have customers that also want to be able to connect Konftel 55Wx to PC over Bluetooth. To solve this we are currently developing a USB Bluetooth dongle that will pair to Konftel 55Wx to get the best user experience for this situation.