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: 983 [Rate centres in NPA 983] [Dial plan for NPA 983]

NXX: 955

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
983-955 A Denver CO   907K ALLO COMMUNICATIONS LLC 656   2025-10-24   
983-955 5 Denver CO   907K ALLO COMMUNICATIONS LLC 656   2025-10-24   

Last updated: Mon, 15 Sep 2025 02:24:40 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.