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: 256 [Rate centres in NPA 256] [Dial plan for NPA 256]

NXX: 421

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
256-421 A Grant AL   792K CHARTER IP ENABLED SERVICES, LLC 477   2025-03-25   
256-421 0 Grant AL   792K CHARTER IP ENABLED SERVICES, LLC 477   2018-02-19   
256-421 1 Grant AL   490J DISH WIRELESS, LLC 477   2022-09-05   

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

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