Jesminder,
Unfortunately ring tones are configured at a phone level. In order to do this you need to go to the phone, push the settings button, select ring type. From there you will get a menu. Line 1 of the menu is the default ring. Line 2 and on corresponding to your line numbers in order. So if you want CallManager line 2 to be a different ring tone then you will select line 3 from the ring type menu, it should have the extension number next to it.
There also might be a way to set it via the web interface. You would want to post in the Ip Communications - Ip Phone services for end users forum.
Please rate any helpful posts
Thanks
Fred