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: 617 [Rate centres in NPA 617] [Dial plan for NPA 617]

NXX: 300

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
617-300 A Cambridge MA FRMNMAWAUMD  7421 AT&T LOCAL 128      
617-300 0 Cambridge MA   4018 LEVEL 3 COMMUNICATIONS, LLC - MA 128   2008-02-21   
617-300 1 Cambridge MA   7421 AT&T LOCAL 128      
617-300 2 Cambridge MA   7421 AT&T LOCAL 128      
617-300 3 Cambridge MA   7421 AT&T LOCAL 128      
617-300 4 Cambridge MA   7421 AT&T LOCAL 128      
617-300 5 Cambridge MA   7421 AT&T LOCAL 128      
617-300 6 Cambridge MA   7421 AT&T LOCAL 128      
617-300 7 Cambridge MA   624H ONVOY SPECTRUM, LLC 128   2021-02-23   
617-300 8 Cambridge MA   4536 XO MASSACHUSETTS, INC. 128   2006-12-14   
617-300 9 Cambridge MA   7421 AT&T LOCAL 128      

Last updated: Sun, 04 Apr 2021 19:28:27 UTC

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.