Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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Chicago Zone 01-Franklin, IL

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NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
312-984 A CHCGILFRDS0  9329 ILLINOIS BELL TEL CO 358      
312-992 A CHCGILFRDS1  9329 ILLINOIS BELL TEL CO 358      

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Last updated: Sun, 07 Dec 2025 22:02:11 UTC

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