Area Code 203-677 located in WALLINGFORD, NEW HAVEN, CT, more detail is as below. Place NPA (Numbering Plan Area) : 203 NXX (Local Number Prefix) : 677 City : WALLINGFORD County : NEW HAVEN State : CT (Connecticut) NXX Use Type : Landline NXX Intro Version : 1998-01-25 FIPS (Federal Information Processing Standards) : 09009 LATA (Local Access Transport Area) : 920 Rate Center : WALLINGFD ZIP Code Count : 1 ZIP Code Frequency : 100 ZIP Code : 06492 Other Information NPANXX : 203677 County Population : 0 Switch CLLI (Common Language Location Identifier) : WLFRCT00DS0 MSA CBSA (Core Based Statistical Area) : New Haven-Milford, CT MSA CBSA Code (Core Based Statistical Area) : 35300 Time Zone : Eastern (GMT -05:00) Observes Daylight Saving Time : Yes Company : SOUTHERN NEW ENGLAND TELEPHONE CO. OCN (Operating Company Number) : 9147 Coverage Area Name : WALLINGFORD Latitude : 41.4539 Longitude : -72.8137 ‹ previous : 203-676 next › : 203-678 Telephone Number List 203-677-0000 ~ 203-677-9999