Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
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NPA: 240 [Rate centres in NPA 240] [Dial plan for NPA 240]

NXX: 399

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
240-399 A Washington Zone 10 MD WASHDCCZDS0  4773 XO MARYLAND, LLC 236      

Last updated: Sun, 04 Apr 2021 19:28:27 UTC

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