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: JHCYTNXCXRY

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
423-656 9 Johnson City TN 478J NUSO, LLC 956   2023-12-30   
423-705 A Johnson City TN 478J NUSO, LLC 956      
423-705 2 Johnson City TN 478J NUSO, LLC 956   2022-02-03   
423-906 2 Johnson City TN 478J NUSO, LLC 956   2024-06-09   
423-906 3 Johnson City TN 478J NUSO, LLC 956   2024-06-09   
423-906 4 Johnson City TN 478J NUSO, LLC 956   2024-09-21   
423-906 5 Johnson City TN 478J NUSO, LLC 956   2024-09-21   

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

Sponsored by: VoIP.ms

Like this site? We accept donations via PayPal.