─────── § 04. NPA RECORD · 240 · FOLIO 0042 OF 0801 ──────────────
240
United States NPA Record
Overlay area code introduced in 1997 to serve western Maryland, including the Washington, D.C.
Overlay area code introduced in 1997 to serve western Maryland, including the Washington, D.C. suburbs, overlaying 301.
IN SERVICEFirst record · 1996
§ 04.05Event Summary
relief planned · 3mandatory dialing · 2planning notice · 2permissive dialing · 1
§ 04.06
Documentary Record · 11 events
CHRONOLOGICAL ORDER
1996-05-01
permissive dialing
Permissive ten-digit local dialing begins in Maryland for 240 overlay preparation
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1996-06-21
relief planned
Overlay relief using NPA 240 for 301 is announced
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1997-01-01
NPA 240 overlays 301 in Maryland
Area code 240 was introduced in 1997 as an overlay for the 301 area in Maryland, providing additional numbering resources for the region.
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1997-05-01
mandatory dialing
Mandatory ten-digit local dialing begins in Maryland for overlay implementation
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1997-06-01
Area code 240 overlays 301 in Maryland
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1997-06-01
mandatory dialing
Mandatory 10-digit dialing for 301/240 overlay complex
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2001-01-03
relief planned
NPA 227 approved as future overlay relief for 240/301
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2022-08-03
planning notice
Implementation of the 227 overlay for 240/301 is approved
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2022-09-27
planning notice
NANPA issues planning letter for NPA 227 overlay implementation
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2022-09-27
relief planned
Approval of 227 overlay for 301/240
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2023-06-14
Area code 227 overlays 240/301 in Maryland
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