Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 657 [Rate centres in NPA 657] [Dial plan for NPA 657]

NXX: 256

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
657-256 A Cypress CA LSANCARCD3S  649C ONVOY, LLC - CA 730   2024-01-23   
657-256 0 Cypress CA   981E BANDWIDTH.COM CLEC, LLC - CA 730   2014-12-20   
657-256 1 Cypress CA   576C TIME WARNER CBL INFO SVCS (CA) DBA TIME WARNER CAB 730   2015-02-06   
657-256 2 Cypress CA   6529 T-MOBILE USA, INC. 730   2015-03-07   
657-256 3 Cypress CA   649C ONVOY, LLC - CA 730   2015-01-05   
657-256 4 Cypress CA   649C ONVOY, LLC - CA 730   2015-01-05   
657-256 5 Cypress CA   649C ONVOY, LLC - CA 730   2015-01-05   
657-256 6 Cypress CA   649C ONVOY, LLC - CA 730   2015-01-05   
657-256 7 Cypress CA   6529 T-MOBILE USA, INC. 730   2015-03-07   
657-256 8 Cypress CA   6529 T-MOBILE USA, INC. 730   2015-02-14   
657-256 9 Cypress CA   6529 T-MOBILE USA, INC. 730   2015-02-14   

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

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