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.
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Switch: CLMAMDOBDS0

Remotes:

Switch Switch name Switch type
CLMAMDSRRS0  COLUMBIA SNOWDEN RIVER  ORM 
GLWDMDGDRS1  GLENWOOD  EXM 
NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
301-310 A Laurel (Baltimore LATA) MD 9212 VERIZON MARYLAND, INC. 238      
410-290 A Columbia MD 9212 VERIZON MARYLAND, INC. 238      
410-309 A Columbia MD 9212 VERIZON MARYLAND, INC. 238      
410-381 A Columbia MD 9212 VERIZON MARYLAND, INC. 238      
410-505 A Ellicott City MD 9212 VERIZON MARYLAND, INC. 238      
443-259 A Columbia MD 9212 VERIZON MARYLAND, INC. 238      

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

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