Every telegraph and telephone corporation shall print and file with the commission schedules showing all the rates and classifications for the transmission of messages or conversations between all of the following points, unless otherwise exempted, in whole or in part, from the filing requirements of subdivision (a) of Section 489:
(a) Between all points within this state and all points outside the state upon its route.
(b) Between all points within this state and all points outside the state upon every route leased, operated, or controlled by it.
(c) Between all points on its route or upon any route, leased, operated, or controlled by it within this state and all points outside the state upon the route of any other telegraph or telephone corporation, whenever a through route and joint rate have been established between any two of these points.