47 CFR 52.7 – Definitions
As used in this subpart:
(a) Area code or numbering plan area (NPA). The term “area code or numbering plan area” refers to the first three digits (NXX) of a ten-digit telephone number in the form NXX-NXX-XXXX, where N represents any one of the numbers 2 through 9 and X represents any one of the numbers 0 through 9.
(b) Area code relief. The term “area code relief” refers to the process by which central office codes are made available when there are few or no unassigned central office codes remaining in an existing area code and a new area code is introduced. Area code relief includes planning for area code “jeopardy,” which is a situation where central office codes may become exhausted before an area code relief plan can be implemented.
(c) Central office (CO) code. The term “central office code” refers to the second three digits (NXX) of a ten-digit telephone number in the form NXX-NXX-XXXX, where N represents any one of the numbers 2 through 9 and X represents any one of the numbers 0 through 9.
(d) Central office (CO) code administrator. The term “central office code administrator” refers to the entity or entities responsible for managing central office codes in each area code.
(e) North American Numbering Plan Administrator (NANPA). The term “North American Numbering Plan Administrator” refers to the entity or entities responsible for managing the NANP.
(f) Billing and Collection Agent. The term “Billing & Collection Agent” (“B&C Agent”) refers to the entity responsible for the collection of funds to support numbering administration for telecommunications services from the United States telecommunications industry and NANP member countries.
(g) Pooling Administrator (PA). The term “Pooling Administrator” refers to the entity or entities responsible for administering a thousands-block number pool.
(h) Contamination. Contamination occurs when at least one telephone number within a block of telephone numbers is not available for assignment to end users or customers. For purposes of this provision, a telephone number is “not available for assignment” if it is classified as administrative, aging, assigned, intermediate, or reserved as defined in § 52.15(f)(1).
(i) Donation. The term “donation” refers to the process by which carriers are required to contribute telephone numbers to a thousands-block number pool.
(j) Inventory. The term “inventory” refers to all telephone numbers distributed, assigned or allocated:
(1) To a service provider; or
(2) To a pooling administrator for the purpose of establishing or maintaining a thousands-block number pool.