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.
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Switch: CMBRMA01DS5

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NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
857-304 3 Watertown MA 7135 TC SYSTEMS, INC. 128   2013-05-10   
857-304 5 Watertown MA 7135 TC SYSTEMS, INC. 128   2014-10-27   
857-304 6 Watertown MA 7135 TC SYSTEMS, INC. 128   2015-06-22   
857-304 8 Watertown MA 7135 TC SYSTEMS, INC. 128   2015-04-20   
857-367 A Watertown MA 7135 TC SYSTEMS, INC. 128      
857-367 6 Watertown MA 7135 TC SYSTEMS, INC. 128   2020-12-07   
857-367 7 Watertown MA 7135 TC SYSTEMS, INC. 128   2021-02-26   
857-383 A Boston MA 7135 TC SYSTEMS, INC. 128      
857-383 4 Boston MA 7135 TC SYSTEMS, INC. 128   2005-12-10   
857-383 5 Boston MA 7135 TC SYSTEMS, INC. 128   2005-12-10   
857-760 2 Watertown MA 7135 TC SYSTEMS, INC. 128   2016-09-15   
857-760 3 Watertown MA 7135 TC SYSTEMS, INC. 128   2016-11-07   

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Last updated: Sat, 01 Aug 2026 03:19:33 UTC

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