Effective May 15, 2013, AT&T revised their interstate access tariffs to split interstate rate elements in the local switching and tandem switching categories between originating and terminating.  Though there were no changes to existing interstate rates, new USOCs to originating and terminating rates will replace the existing USOCs for the purpose of billing access charges. And what about Dedicated End Office Trunk Port and Dedicated Tandem Trunk Port? They will be billed as originating and terminating rates, which will be based on a POU factor of 50%.