The administration of the scheme of logical addresses, i.e., telephone numbers, used in the global switched telephone network (GSTN) and the national public switched telephone networks (PSTNs) that compose it.The ITU-T is responsible for international numbering plan administration, and individual nations or regions have similar responsibilities within their domains.The North American Numbering Plan (NANP), for example, defines the telephone numbering scheme in the area loosely described as North America.The ITU-T E.164 recommendation (The International Public Telecommunication Numbering Plan) specifies the current international NPA convention at a maximum of 15 digits, although the number of digits required for calling within a nation varies. In many cases, numbering schemes vary within the same country; for example, six- and seven-digit telephone numbers coexist in Namibia and many other countries. In the countries within the NANP, the dialing scheme is +CC.NPA.NXX.xxxx, with the fields defined as follows:
(1) (Numbering Plan Area) The Bellcore/Telcordia telephone area code system in use in the U.S., Canada, Alaska, Hawaii and islands in the Caribbean. See NPA code.
(2) (Network Professional Association, San Diego, CA, www.npanet.org) A membership organization founded in 1994 that is dedicated to advancing computer professionals who specialize in networking. It developed and funded the Certified Network Professional examination, the leading non-vendor examination in network technology. The NPA evolved out of the CNE Professional Association (CNEPA), which was formed in 1990. See CNP.