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: 551 [Rate centres in NPA 551] [Dial plan for NPA 551]

NXX: 423

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
551-423 A Hackensack NJ   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 224   2025-07-04   
551-423 8 Hackensack NJ   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 224   2025-07-04   
551-423 9 Hackensack NJ   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 224   2025-07-04   

Last updated: Sun, 01 Jun 2025 02:18:11 UTC

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