Local Calling Guide

Area code/prefix search

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

NXX: 255

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-255 A Manchester NH MNCHNHCOY0X  425J CSC WIRELESS, LLC 122      
603-255 0 Manchester NH   624H ONVOY SPECTRUM, LLC 122   2022-01-07   
603-255 1 Manchester NH   624H ONVOY SPECTRUM, LLC 122   2022-01-07   
603-255 2 Manchester NH   425J CSC WIRELESS, LLC 122   2020-04-17   
603-255 3 Manchester NH   637E ONVOY, LLC - NH 122   2020-05-10   
603-255 4 Manchester NH   637E ONVOY, LLC - NH 122   2020-06-01   
603-255 5 Manchester NH   637E ONVOY, LLC - NH 122   2020-07-02   
603-255 6 Manchester NH   8299 TELEPORT COMMUNICATIONS AMERICA, LLC - NH 122   2020-05-23   
603-255 7 Manchester NH   637E ONVOY, LLC - NH 122   2020-09-18   
603-255 8 Manchester NH   637E ONVOY, LLC - NH 122   2021-03-08   
603-255 9 Manchester NH   478J NUSO, LLC 122   2020-10-15   

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

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