Offsite — As of April 1999, there were 105,291 NPA/NXX’s (area code plus exchanges) registered for use in the USA and Canada. These prefixes are served by “central offices” located at some 24644 “wire centers”. It is at these wire centers that “local loops” to customers are terminated and branch circuits to other offices originate. This map shows the distribution of wire centers ...
Offsite — Find international dialing codes. In the US, dial: 011 + Country Code + Phone Number.