Local Calling Guide

Area code/prefix search

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

NXX: 377

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-377 A Merrimack NH MNCHNHCOCM1  6889 OMNIPOINT MIAMI E LICENSE, LLC 122      
603-377 0 Merrimack NH   6889 OMNIPOINT MIAMI E LICENSE, LLC 122      
603-377 1 Merrimack NH   6889 OMNIPOINT MIAMI E LICENSE, LLC 122   2016-11-19   
603-377 2 Merrimack NH   6889 OMNIPOINT MIAMI E LICENSE, LLC 122   2021-08-07   
603-377 3 Merrimack NH   637E ONVOY, LLC - NH 122   2022-01-15   
603-377 4 Merrimack NH   637E ONVOY, LLC - NH 122   2022-08-28   
603-377 5 Merrimack NH   073H TELNYX LLC 122   2023-08-26   
603-377 6 Merrimack NH   5562 METROPCS, INC. 122      
603-377 7 Merrimack NH   318J COMCAST IP PHONE, LLC 122   2012-04-30   
603-377 8 Merrimack NH   637E ONVOY, LLC - NH 122   2021-11-13   
603-377 9 Merrimack NH   145J TERRA NOVA TELECOM INC. 122   2021-05-27   

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

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