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: 551 [Rate centres in NPA 551] [Dial plan for NPA 551]

NXX: 321

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
551-321 A Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224      
551-321 0 Park Ridge NJ NWRKNJ0293Z  073H TELNYX LLC 224   2022-01-03   
551-321 1 Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224   2020-09-19   
551-321 2 Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224   2020-09-19   
551-321 3 Park Ridge NJ   637C ONVOY, LLC - NJ 224   2025-03-09   
551-321 4 Park Ridge NJ HCKNNJHKX4X  624H ONVOY SPECTRUM, LLC 224   2021-05-07   
551-321 5 Park Ridge NJ HCKNNJHKX4X  624H ONVOY SPECTRUM, LLC 224   2022-04-17   
551-321 6 Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224   2021-03-12   
551-321 7 Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224   2021-03-12   
551-321 8 Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224   2021-07-15   
551-321 9 Park Ridge NJ NWRKNJMDDSK  637C ONVOY, LLC - NJ 224   2021-07-15   

Last updated: Sun, 27 Apr 2025 12:48:38 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.