Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 840 [Rate centres in NPA 840] [Dial plan for NPA 840]

NXX: 289

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
840-289 A Diamond Bar CA   649C ONVOY, LLC - CA 730   2026-09-11   
840-289 0 Diamond Bar CA   649C ONVOY, LLC - CA 730   2026-09-11   
840-289 1 Diamond Bar CA   373F PEERLESS NETWORK OF CALIFORNIA, LLC - CA 730   2026-09-20   
840-289 8 Diamond Bar CA   624H ONVOY SPECTRUM, LLC 730   2026-09-14   
840-289 9 Diamond Bar CA   624H ONVOY SPECTRUM, LLC 730   2026-09-14   

Last updated: Tue, 01 Sep 2026 00:40:05 UTC

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