Disclosed are methods and apparatuses for selecting an interexchange telephone call carrier, selecting a route to the selected carrier, and establishing a call path on the selected route to the selected carrier in a multi-carrier environment. To select a carrier, dialed digits incoming from a terminal...http://www.google.fr/patents/US4565903?utm_source=gb-gplus-shareBrevet US4565903 - Telephone interexchange carrier selection
