NumberResearchThousands-blocks in 231-803
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026
The ten 1,000-number thousand-blocks inside prefix 231-803 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 231 blocks
Most active assignees, all time — NPA 231
New assignments by month
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 231-803-0XXX | 0000–0999 | Available | MORLEY | MI | ||
| 2014-06-17 | 231-803-1XXX | 1000–1999 | Assigned | DAYSTARR LLC DBA DAYSTARR COMMUNICATIONS | 993L | MORLEY | MI |
| — | 231-803-2XXX | 2000–2999 | Available | MORLEY | MI | ||
| 2016-02-23 | 231-803-3XXX | 3000–3999 | Assigned | ONVOY, LLCV - MI | 543C | MORLEY | MI |
| 2004-06-22 | 231-803-4XXX | 4000–4999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MI | 6120 | MORLEY | MI |
| 2011-08-11 | 231-803-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | MORLEY | MI |
| 2016-02-23 | 231-803-6XXX | 6000–6999 | Assigned | ONVOY, LLCV - MI | 543C | MORLEY | MI |
| 2015-08-17 | 231-803-7XXX | 7000–7999 | Assigned | CENTURYLINK COMMUNICATIONS, LLC | 508J | MORLEY | MI |
| — | 231-803-8XXX | 8000–8999 | Available | MORLEY | MI | ||
| — | 231-803-9XXX | 9000–9999 | Available | MORLEY | MI |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.