Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 857 [Rate centres in NPA 857] [Dial plan for NPA 857]

NXX: 421

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
857-421 A Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-01   
857-421 0 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-20   
857-421 1 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-20   
857-421 2 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-20   
857-421 3 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-20   
857-421 4 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-20   
857-421 5 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-20   
857-421 6 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2025-09-19   
857-421 7 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-01   
857-421 8 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-01   
857-421 9 Brookline MA NRTNMAAACM4  6889 OMNIPOINT MIAMI E LICENSE, LLC 128   2024-09-01   

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

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