This video is showing the mobile client:
Note that the prensence stat dosen't change to "in a call" ....... let's hope that this is a Bug ;) .....but I think that might be a limitation because of technical dependencies on the mobile network.
On some Mobile networks you aren't able to be online and talk on the phone at the same time, thereby it's not possibly to set the prensence stat to "in a call".
This video is about the managment console.
John Weston just love OCS :) see the video "A day in the life of UC, my laptop is my phone"
John Weston demos for the Dallas Chapter of AITP(Association for IT Professionals). This time he shows them how his laptop is his phone. How UC brings together both the computer and phone networks.