Area Code 203: Comprehensive Guide to Technical Details and Data
Area code 203 is part of the North American Numbering Plan (NANP) and serves the southwestern region of Connecticut, covering major cities such as Bridgeport, New Haven, and Stamford.
Technical Specifications of Area Code 203
- NPA Code: 203
- Type: Overlay (with area code 475)
- Implementation Date: 1947
- State: Connecticut
Geographic Coverage
Area code 203 primarily serves the southwestern part of Connecticut, including Fairfield County, New Haven County, and a small portion of Litchfield County.
Major Cities Served
- Bridgeport: 41.16704°N, 73.20483°W
- Danbury: 41.39482°N, 73.45401°W
- East Haven: 41.27621°N, 72.86843°W
- Meriden: 41.53815°N, 72.80704°W
- Milford: 41.22232°N, 73.05650°W
- Naugatuck: 41.48593°N, 73.05066°W
- New Haven: 41.30815°N, 72.92816°W
- North Haven: 41.39093°N, 72.85954°W
- Norwalk: 41.11760°N, 73.40790°W
- Shelton: 41.31649°N, 73.09316°W
- Stamford: 41.05343°N, 73.53873°W
- Stratford: 41.18454°N, 73.13317°W
- Trumbull: 41.24287°N, 73.20067°W
- Waterbury: 41.55815°N, 73.05150°W
- West Haven: 41.27065°N, 72.94705°W
- Westport: 41.14149°N, 73.35790°W
Numbering Statistics
- Total Numbers Available: Approximately 7.8 million
- Utilization Rate: 72%
- Exhaust Projection: 2024
Network Infrastructure
Major Carriers
- AT&T: 35%
- Verizon: 30%
- T-Mobile: 20%
- Other: 15%
Types of Services
- Landline
- Wireless
- VoIP
Regulatory Framework
- Regulatory Body: Connecticut Department of Public Utility Control
- Dialing Requirements: 10-digit dialing for all calls
- NANPA Regulations: Compliance with NANPA's overlay and area code relief planning
Historical Milestones
- 1947: Area code 203 established as one of the original North American area codes.
- 1995: Area code 860 created, reducing the geographic area of 203.
- 2009: Area code 475 overlaid on 203, introducing 10-digit dialing.
Conclusion
Area code 203 is a critical component of Connecticut's telecommunications infrastructure, serving a densely populated and economically significant region. Its overlay with area code 475 and the implementation of 10-digit dialing reflect the area's growing demand for telephone numbers. For more information, visit the North American Numbering Plan Administration.