In order to make page calls you must have access to a paging short code provided by the system administrator or a Page feature button.
You can use the self-administration function to assign one of your phone’s feature buttons as a Page button. See Programmable Feature Buttons.
If the short code or the paging button have been pre-configured with an extension number, the user or group at that number is paged if available.
If the short code of paging button does not have a pre-configured extension number, it allows extension number entry when used.