Local Calling Guide

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

NXX: 420

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-420 A Merrimack NH MNCHNHACDS0  7778 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 122      
603-420 0 Merrimack NH MNCHNHCO23Z  073H TELNYX LLC 122   2022-10-21   
603-420 1 Merrimack NH   829J PAETEC ITEL, LLC 122   2001-09-24   
603-420 2 Merrimack NH MNCHNHCOX9Z  637E ONVOY, LLC - NH 122   2023-03-31   
603-420 4 Merrimack NH   145J TERRA NOVA TELECOM INC. 122   2025-10-29   
603-420 5 Merrimack NH   829J PAETEC ITEL, LLC 122   2006-05-01   
603-420 7 Merrimack NH MNCHNHCOX9Z  637E ONVOY, LLC - NH 122   2022-12-02   
603-420 8 Merrimack NH MNCHNHIE6MD  318J COMCAST IP PHONE, LLC 122   2009-03-22   
603-420 9 Merrimack NH MNCHNHACDS0  7778 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH 122      

Last updated: Mon, 15 Sep 2025 02:24:40 UTC

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