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: 423 [Rate centres in NPA 423] [Dial plan for NPA 423]

NXX: 743

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
423-743 A Erwin TN ERWNTNXARS0  4510 UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN 956      

Last updated: Sat, 04 Jul 2026 13:07:56 UTC

Sponsored by: VoIP.ms

Like this site? We accept donations via PayPal.