Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 603 [Rate centres in NPA 603] [Dial plan for NPA 603]

NXX: 405

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-405 A Somersworth NH DOVRNHTHXEX  8299 TELEPORT COMMUNICATIONS AMERICA, LLC - NH 122      
603-405 0 Somersworth NH   314C IDT AMERICA, CORP. - NH 122   2020-12-24   
603-405 1 Somersworth NH   073H TELNYX LLC 122   2024-07-04   
603-405 2 Somersworth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2017-02-16   
603-405 6 Somersworth NH   8299 TELEPORT COMMUNICATIONS AMERICA, LLC - NH 122   2016-06-17   
603-405 8 Somersworth NH   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2017-05-04   

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

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