Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 312 [Rate centres in NPA 312] [Dial plan for NPA 312]

NXX: 452

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
312-452 A Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 0 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 1 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 2 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 3 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 4 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   

Last updated: Thu, 20 Nov 2025 13:34:34 UTC

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