The University has invested in a product called Jabber which works with the phone system giving some very useful features. You can install the Jabber software on your computer or mobile phone and have your calls find you on these devices in addition to the phone on your desk.
You can also use it for instant messaging and desk to desk video calls. Please see the University Information Services Jabber Guide for more information about installing and using the different features. The University of Stanford has some good documentation that might also be of use https://uit.stanford.edu/service/jabber/quick-guides
Please note that Cisco Jabber requires its own password. This can be set in My.Phone Phone Options. If you do not see a “Cisco Password” section on that page, you have not been enabled for Jabber and you should contact your Telephone Liaison Officer to arrange for this to be setup.