NumberResearchNumbering Change Events (Relief, Overlays & Splits)
Free access · version 2026-09-18 (latest) · 271 rows · CC BY 4.0
Relief decisions, overlays, splits and jeopardy declarations consolidated from NANPA planning letters, with permissive/mandatory dialing dates extracted verbatim.
Schema7 columns
| Column | Description |
|---|---|
| slug | stable event identifier |
| event_type | overlay | split | new_npa | jeopardy | other |
| npa | primary NPA |
| related_npa | new/overlay NPA where applicable |
| permissive_start | permissive dialing start date |
| mandatory_date | mandatory dialing date |
| effective_date | new code activation date |
Samplefirst 8 rows
| slug | event_type | npa | related_npa | permissive_start | mandatory_date | effective_date |
|---|---|---|---|---|---|---|
| overlay-npa-912-565-ga-pl-63... | overlay | 912 | 565 | — | — | — |
| new-npa-npa-543-pl-636 | new_npa | 543 | — | — | — | — |
| other-npa-542-pl-635 | other | 542 | — | — | — | 2026-05-26 |
| new-npa-npa-542-pl-634 | new_npa | 542 | — | — | — | 2026-03-16 |
| other-npa-945-tx-pl-537 | other | 945 | — | — | — | — |
| other-npa-948-va-pl-536 | other | 948 | — | — | — | — |
| overlay-npa-405-572-ok-pl-53... | overlay | 405 | 572 | — | — | — |
| other-npa-x-ar-pl-437 | other | — | — | — | — | — |
Known limitations
Dialing dates are present only where the planning letter states them verbatim (quote-verified). Some older planning letters are scanned images without a text layer and are not yet parsed.
Machine-readable catalog: /datasets.json · /data-sources.json. Cited versions never change — a version URL always resolves to the exact release. See methodology and licensing.