 The first three digits of a NANP number are the numbering plan area code, NPA code, or simply "NPA", the next three, "NXX", identify the central office, and the last four are the line number of an individual office.The telephone industry's current recommendation assumes first that mandatory dialing of all ten digits is required to complete telephone numbers, even for a local call, throughout the North American Numbering Plan area, which includes many Caribbean and Pacific territories and nations.The plan proposes the insertion of "00" or "11" between the NPA and the NXX, to produce 12-digit numbers.