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: 640

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-640 A Bel Air MD   829J PAETEC ITEL, LLC 238   2025-04-01   
443-640 0 Bel Air MD   829J PAETEC ITEL, LLC 238      
443-640 1 Bel Air MD   829J PAETEC ITEL, LLC 238      
443-640 2 Bel Air MD   829J PAETEC ITEL, LLC 238      
443-640 3 Bel Air MD   829J PAETEC ITEL, LLC 238      
443-640 4 Bel Air MD   318J COMCAST IP PHONE, LLC 238   2008-04-30   
443-640 5 Bel Air MD   6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 238   2009-02-02   
443-640 6 Bel Air MD   420C ARMSTRONG TELECOMMUNICATIONS, INC. - MD 238   2008-09-08   
443-640 7 Bel Air MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2012-03-16   
443-640 8 Bel Air MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238   2008-04-21   
443-640 9 Bel Air MD   073H TELNYX LLC 238   2021-03-04   

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.