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: 620

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-620 A Waterloo MD CLMAMDNIDS1  7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      
443-620 0 Waterloo MD BLTMMDCH45Z  071F BANDWIDTH.COM CLEC, LLC - MD 238   2010-02-22   
443-620 1 Waterloo MD BLTMMDCH42Z  876D ONVOY, LLC - MD 238   2021-04-29   
443-620 2 Waterloo MD BLTOMDKHDS0  7228 MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD 238   2020-06-05   
443-620 3 Waterloo MD BLTMMDCH45Z  071F BANDWIDTH.COM CLEC, LLC - MD 238   2011-01-09   
443-620 4 Waterloo MD BLTMMDCH45Z  071F BANDWIDTH.COM CLEC, LLC - MD 238   2011-04-04   
443-620 5 Waterloo MD BLTMMDCHXFX  318J COMCAST IP PHONE, LLC 238   2015-01-05   
443-620 6 Waterloo MD BLTMMDSN6MD  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 238   2012-12-01   
443-620 7 Waterloo MD BLTMMDDN2MD  508J CENTURYLINK COMMUNICATIONS, LLC 238   2014-04-02   
443-620 8 Waterloo MD BLTMMDCH45Z  071F BANDWIDTH.COM CLEC, LLC - MD 238   2015-03-15   
443-620 9 Waterloo MD CLMAMDNIDS1  7325 TELEPORT COMMUNICATIONS AMERICA, LLC - MD 238      

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

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