There are technical, legal and financial considerations in providing local telephone service. Understanding how calls are passed between competing local carriers and between local carriers, resellers and interexchange carriers is important in comprehending the structure of the industry.
The following should be considered within the context of local calling:
Transport— The line from a home or business to the central office.
Switching— The central office switch directs calls to their destination. It also has links to billing and enhanced feature systems such as voice mail and caller ID.
Terminating transport— The transmission of the call to its end site, or destination.
Signaling— Signals in the network ...