Local Calling Guide

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

NXX: 633

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-633 A Milford NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122      
603-633 0 Milford NH   6386 BELL ATLANTIC MOBILE, INC 122   2022-06-20   
603-633 1 Milford NH   073H TELNYX LLC 122   2022-10-06   
603-633 2 Milford NH   637E ONVOY, LLC - NH 122   2023-04-06   
603-633 3 Milford NH   637E ONVOY, LLC - NH 122   2023-08-20   
603-633 4 Milford NH   637E ONVOY, LLC - NH 122   2022-09-29   
603-633 5 Milford NH   637E ONVOY, LLC - NH 122   2022-09-29   
603-633 6 Milford NH   318J COMCAST IP PHONE, LLC 122   2023-02-17   
603-633 7 Milford NH   318J COMCAST IP PHONE, LLC 122   2023-02-17   
603-633 8 Milford NH   637E ONVOY, LLC - NH 122   2022-11-26   
603-633 9 Milford NH   318J COMCAST IP PHONE, LLC 122   2023-02-17   

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

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