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: BLTMMDSNDS6

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
240-324 A Ashton (Baltimore LATA) MD 281E YMAX COMMUNICATIONS CORP. - MD 238      
443-982 A Baltimore MD 281E YMAX COMMUNICATIONS CORP. - MD 238      

Last updated: Thu, 01 Jan 2026 03:59:49 UTC

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