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.
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Switch: DNVTCOZIAMD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
720-923 A Denver CO 181J ADVANCED TELECOM SOLUTIONS, LLC 656      
720-923 0 Denver CO 181J ADVANCED TELECOM SOLUTIONS, LLC 656   2018-10-06   

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

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