Great question!
Easy answer:
Skype for Business.
Yep, that’s it!
So far, no other softphones work for answering calls with the LH250 and LH255, not even the free home-user version of Skype.
However, even if you can’t answer and end calls, the volume and mute buttons on the cord will still work for you.
(415) 351-5857
kyle@headsets.com