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: 312 [Rate centres in NPA 312] [Dial plan for NPA 312]

NXX: 574

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
312-574 A Chicago Zone 01-Franklin IL CHCGILFRDS1  9329 ILLINOIS BELL TEL CO 358      
312-574 0 Chicago Zone 01-Franklin IL CHCGILWBXDZ  984E BANDWIDTH.COM CLEC, LLC - IL 358   2010-03-04   
312-574 1 Chicago Zone 01-Franklin IL CHCGILDTDS3  5447 ACCESS ONE, INC. - IL 358   2010-07-15   
312-574 2 Chicago Zone 01-Franklin IL CHCGILFRDS0  9329 ILLINOIS BELL TEL CO 358      
312-574 3 Chicago Zone 01-Franklin IL CHCGILWBXDZ  984E BANDWIDTH.COM CLEC, LLC - IL 358   2011-01-16   
312-574 4 Chicago Zone 01-Franklin IL CHCGILFRDS0  9329 ILLINOIS BELL TEL CO 358      
312-574 5 Chicago Zone 01-Franklin IL CHCGILFRDS1  9329 ILLINOIS BELL TEL CO 358      
312-574 6 Chicago Zone 01-Franklin IL CHCGILFRDS1  9329 ILLINOIS BELL TEL CO 358      
312-574 7 Chicago Zone 01-Franklin IL CHCGILFRDS1  9329 ILLINOIS BELL TEL CO 358      
312-574 8 Chicago Zone 01-Franklin IL CHCGILFRDS1  9329 ILLINOIS BELL TEL CO 358      
312-574 9 Chicago Zone 01-Franklin IL CHCGILFRDS0  9329 ILLINOIS BELL TEL CO 358      

Last updated: Fri, 22 Mar 2024 03:02:44 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.