What is presence?
Presence is the ability of a person or a device to communicate with others and display levels of availability. Both users and programs determine availability. If a calendar indicates someone has a meeting at 10 a.m., a user’s presence status automatically changes at that time. If a user picks up the phone and the PBX or IP-PBX is integrated with the collaboration system, the user’s presence status will indicate he or she is on a call.