Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 203 [Rate centres in NPA 203] [Dial plan for NPA 203]

NXX: 421

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
203-421 A Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 0 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 1 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 2 Madison CT HRFRCTCR3MD  318J COMCAST IP PHONE, LLC 920   2014-08-28   
203-421 3 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 4 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 5 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 6 Madison CT HRFRCTCR3MD  318J COMCAST IP PHONE, LLC 920   2010-09-16   
203-421 7 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 8 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      
203-421 9 Madison CT MDSNCT02RS0  9147 SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 920      

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

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