"Exchange" means a geographical area for the administration of telecommunications services, established and described by the tariff of a telecommunications carrier providing local exchange telecommunications service, and consisting of one or more contiguous central offices, together with associated facilities used in providing such local exchange telecommunications service. To the extent practicable, a municipality, city, or village shall not be located in more than one exchange unless the municipality, city, or village is located in more than one exchange through annexation that occurs after the establishment of the exchange boundary.
220 ILCS 5/13-206