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: 443 [Rate centres in NPA 443] [Dial plan for NPA 443]

NXX: 378

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-378 A Baltimore MD BLTMMDCH40Z  6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238   2024-02-09   
443-378 0 Baltimore MD BLTMMDCH40Z  6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238   2005-07-25   
443-378 1 Baltimore MD CLMAMDORGT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2024-01-13   
443-378 2 Baltimore MD CLMAMDORGT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2024-01-13   
443-378 3 Baltimore MD CLMAMDJTAMD  2589 US LEC OF MARYLAND, INC. 238   2006-02-10   
443-378 4 Baltimore MD BLTMMDCHDS2  9212 VERIZON MARYLAND, INC. 238   2006-02-20   
443-378 5 Baltimore MD BLTMMDCHXNX  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238   2004-09-23   
443-378 6 Baltimore MD CLMAMDORGT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2024-01-13   
443-378 7 Baltimore MD BLTMMDCHXNX  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238   2004-09-23   
443-378 8 Baltimore MD BLTMMDCHXNX  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238   2004-09-23   
443-378 9 Baltimore MD   876D ONVOY, LLC - MD 238   2024-02-24   

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

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.