Sec. 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.
    (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.

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    (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.