Local Calling Guide

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NPA: 603 [Rate centres in NPA 603] [Dial plan for NPA 603]

NXX: 570

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-570 A Portsmouth NH DOVRNHTHXEX  8299 TELEPORT COMMUNICATIONS AMERICA, LLC - NH 122      
603-570 0 Portsmouth NH   8299 TELEPORT COMMUNICATIONS AMERICA, LLC - NH 122   2014-03-10   
603-570 1 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2015-08-11   
603-570 2 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2006-10-17   
603-570 3 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2001-07-13   
603-570 4 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2001-07-13   
603-570 5 Portsmouth NH   829J PAETEC ITEL, LLC 122   2004-11-18   
603-570 6 Portsmouth NH   7778 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 122   2012-03-30   
603-570 7 Portsmouth NH   8468 FREEDOM RING COMMUNICATIONS, LLC 122   2007-06-13   
603-570 8 Portsmouth NH   6386 BELL ATLANTIC MOBILE, INC 122   2018-01-10   
603-570 9 Portsmouth NH   7778 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 122      

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

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