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: 203 [Rate centres in NPA 203] [Dial plan for NPA 203]

NXX: 203

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
203-203 A Greenwich CT NYCMNYBXDSL  639C ONVOY, LLC - CT 132   2024-11-21   
203-203 0 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 1 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 2 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 3 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 4 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 5 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 6 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 7 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 8 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   
203-203 9 Greenwich CT   639C ONVOY, LLC - CT 132   2024-11-21   

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.