Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 443 [Rate centres in NPA 443] [Dial plan for NPA 443]

NXX: 399

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-399 A Dundalk MD   876D ONVOY, LLC - MD 238      
443-399 0 Dundalk MD   876D ONVOY, LLC - MD 238   2024-10-21   
443-399 1 Dundalk MD   876D ONVOY, LLC - MD 238   2024-10-21   
443-399 2 Dundalk MD   876D ONVOY, LLC - MD 238   2012-10-08   
443-399 3 Dundalk MD   071F BANDWIDTH.COM CLEC, LLC - MD 238   2015-05-23   
443-399 5 Dundalk MD   568G PEERLESS NETWORK OF MARYLAND, LLC 238   2020-10-28   
443-399 6 Dundalk MD   071F BANDWIDTH.COM CLEC, LLC - MD 238   2015-05-23   
443-399 7 Dundalk MD   508J CENTURYLINK COMMUNICATIONS, LLC 238   2014-04-02   
443-399 8 Dundalk MD   318J COMCAST IP PHONE, LLC 238   2008-03-19   
443-399 9 Dundalk MD   515J IP HORIZON LLC 238   2013-09-06   

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

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