For Wireless Headsets, use this bluetooth adaptor for IP phone series 300 and above.
Bluetooth &EHS wireless headset module. The module can connect to the USB interface which is at the back of the phone (ES/GS320 ES/GS330 ES/GS410 and ES/GS620), providing Bluetooth, Wireless Headset Adapter and USB_5V Power Charger function. Support plug and play.