Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

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

NXX: 923

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-923 A Rochester NH MNCHNHCOX8Z  4017 LEVEL 3 COMMUNICATIONS, LLC - NH 122      
603-923 0 Rochester NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122      
603-923 1 Rochester NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122      
603-923 2 Rochester NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122      
603-923 3 Rochester NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122      
603-923 4 Rochester NH MNCHNHCOX8Z  4017 LEVEL 3 COMMUNICATIONS, LLC - NH 122      
603-923 5 Rochester NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122      
603-923 7 Rochester NH MNCHNHACAMD  6386 BELL ATLANTIC MOBILE, INC 122      
603-923 8 Rochester NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122      
603-923 9 Rochester NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122      

Last updated: Wed, 20 Nov 2024 21:20:06 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.