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.

Switch: BLTMMDSNNMD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
443-657 A Randallstown MD 7591 LEVEL 3 TELECOM OF MARYLAND, LLC - MD 238      
443-657 2 Randallstown MD 7591 LEVEL 3 TELECOM OF MARYLAND, LLC - MD 238      

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

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