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: 400

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
603-400 A Hollis NH MNCHNHCO43Z  792K CHARTER IP ENABLED SERVICES, LLC 122      
603-400 0 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2011-10-18   
603-400 1 Hollis NH MNCHNHCO43Z  792K CHARTER IP ENABLED SERVICES, LLC 122   2011-10-15   
603-400 2 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2013-11-04   
603-400 3 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2017-04-29   
603-400 4 Hollis NH   6889 OMNIPOINT MIAMI E LICENSE, LLC 122   2017-02-27   
603-400 5 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2016-10-01   
603-400 6 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2016-07-09   
603-400 7 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2016-03-26   
603-400 8 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2015-09-22   
603-400 9 Hollis NH DRRYNHBC1MD  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 122   2014-11-11   

Last updated: Sat, 05 Apr 2025 03:03:23 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.