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.

Switch: OKLDCAOL1MD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
510-550 A Oakland: Main-Piedmont DA CA 8690 GLOBAL CROSSING LOCAL SERVICES, INC. - CA 722      
510-550 0 Oakland: Main-Piedmont DA CA 8690 GLOBAL CROSSING LOCAL SERVICES, INC. - CA 722   2002-08-17   

Last updated: Sun, 01 Jun 2025 02:18:11 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.