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: 657 [Rate centres in NPA 657] [Dial plan for NPA 657]

NXX: 238

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
657-238 A Cypress CA TRNECAGB7MD  6529 T-MOBILE USA, INC. 730      
657-238 0 Cypress CA   829J PAETEC ITEL, LLC 730   2014-06-27   
657-238 1 Cypress CA   649C ONVOY, LLC - CA 730   2014-09-19   
657-238 2 Cypress CA   8826 LEVEL 3 COMMUNICATIONS, LLC - CA 730   2014-07-20   
657-238 3 Cypress CA   649C ONVOY, LLC - CA 730   2014-09-19   
657-238 4 Cypress CA   899D METROPCS NETWORKS, LLC 730   2014-09-22   
657-238 5 Cypress CA   8826 LEVEL 3 COMMUNICATIONS, LLC - CA 730   2014-10-20   
657-238 6 Cypress CA   6010 NEW CINGULAR WIRELESS PCS, LLC 730   2019-09-14   
657-238 7 Cypress CA   6529 T-MOBILE USA, INC. 730   2014-06-29   
657-238 8 Cypress CA   981E BANDWIDTH.COM CLEC, LLC - CA 730   2015-05-21   
657-238 9 Cypress CA   6529 T-MOBILE USA, INC. 730   2014-06-26   

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

Sponsored by: LES.NET

Like this site? We accept donations via PayPal.