It's similar to a switch-hook. I don't believe there is any advanced feature of this button. This is how we use it during conferences:
Rec've call from customer
Hit Conference (dial outside party - preface call)
Hit Conference again (bring all parties together)
Hit Conference - 1 last time (this places you on hold)
Hit headset button (this removes you from call)
Hope this helps,
Chris
We are what we repeatedly do. Excellence, then, is not an act but a habit. ARISTOTLE 384-322 B.C.