Editing Interexchange carrier (section)

==Call handling==
An interexchange carrier handles traffic between [[telephone exchange]]s. Telephone exchanges are identified in the United States by the three-digit area code (NPA) and the central office prefix, which is the first three digits of the local telephone number (NPA-NXX). Different exchanges, or central offices, generally serve different geographic areas.

For voice traffic transfer, IXCs use Tandem switches and SS7 signaling or [[softswitch]]es and [[VoIP]] protocols and error correction{{citation needed|date=October 2012}} [[ITSP]]s can thereby connect between VoIP to [[Landline|POTS]], computer to computer, computer to phone, and [[Internet Protocol]] devices to other phone services.<ref>{{cite web|title=About Softswitches in general|url=http://www.ixc.ua/telecom-industry-concepts|publisher=IXC|date=19 September 2012|access-date=19 September 2012|archive-date=17 August 2012|archive-url=https://web.archive.org/web/20120817171907/http://www.ixc.ua/telecom-industry-concepts|url-status=dead}}</ref>