the company I work for uses "Starface" for VoIP. Starface comes automatically with a Jabber / XMPP-Server and with the Jabber-Clients "PSI" and shows if the clients are active. (--> the users can be called).
It would be perhaps useful at PBXes too, if each extension would automatically receive an jabber-ID (e. g.pbxesisti-xxx@pbxes.org) which could be registered in a jabber client knowing us if the extension is activated or the call will be forwarded.
A jabber-Server could be also used to improve the communication among the extensions via
- filetransfer
- audiotransfer
- and secure chat (OTR/TLS)
