Sennheiser DW Series User Manual page 27

Making calls using the headset
26 | DW Series - User Guide
Managing calls using the "HeadSetup" call control functionality
Accepting a call: The softphone signals that you are receiving a call. You
hear a ring tone in the headset. Press the Link button on the headset to
accept the call.
Making a call: Start the call using your softphone, the audio signal is
automatically transmitted to the headset.
Ending a call: Press the Link button. If the other party hangs up, your
softphone and your headset become automatically ready to receive the
next call.