Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 331 [Rate centres in NPA 331] [Dial plan for NPA 331]

NXX: 337

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
331-337 A Oswego IL BURGILAHGT3  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 358   2025-02-23   
331-337 6 Oswego IL BURGILAHGT3  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 358   2026-03-01   
331-337 7 Oswego IL BURGILAHGT3  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 358   2025-02-24   
331-337 8 Oswego IL BURGILAHGT3  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 358   2025-02-23   
331-337 9 Oswego IL BURGILAHGT3  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 358   2025-02-23   

Last updated: Sat, 01 Aug 2026 03:19:33 UTC

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